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A library for generating preview (thumbnails, text or json overview) for file-based content

Project description

==================================
Preview-generator Documentation
==================================

.. image:: https://travis-ci.org/algoo/preview-generator.svg?branch=master
:target: https://travis-ci.org/algoo/preview-generator
------------
Presentation
------------

preview-generator is a library for generating preview - thumbnails, pdf, text and json overview
for all your file-based content. This module gives you access to jpeg, pdf, text, htlm and json
preview of virtually any kind of file. It also includes a cache mechanism so you do not have to
care about preview storage.

By creating this module, the goal was to delegate the responsibility of building preview
of files managed by `tracim <https://github.com/tracim/tracim/.>`_.


----------------------
Supported file formats
----------------------

Here is an overview of supported file formats:

+----------------------------------------------------------------------------------+-------------+
+ MIME type + Extension +
+==================================================================================+=============+
| **Images - based on WAND (image magick)** |
+----------------------------------------------------------------------------------+-------------+
| application/postscript | .ps |
+----------------------------------------------------------------------------------+-------------+
| image/x-jg | .art |
+----------------------------------------------------------------------------------+-------------+
| image/x-ms-bmp | .bmp |
+----------------------------------------------------------------------------------+-------------+
| text/plain | .ksh |
+----------------------------------------------------------------------------------+-------------+
| image/x-canon-cr2 | .cr2 |
+----------------------------------------------------------------------------------+-------------+
| image/x-canon-crw | .crw |
+----------------------------------------------------------------------------------+-------------+
| application/dicom | .dcm |
+----------------------------------------------------------------------------------+-------------+
| application/x-director | .dcr |
+----------------------------------------------------------------------------------+-------------+
| image/x-epson-erf | .erf |
+----------------------------------------------------------------------------------+-------------+
| image/gif | .gif |
+----------------------------------------------------------------------------------+-------------+
| text/x-chdr | .h |
+----------------------------------------------------------------------------------+-------------+
| text/html | .htm |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.microsoft.icon | .ico |
+----------------------------------------------------------------------------------+-------------+
| application/x-info | .info |
+----------------------------------------------------------------------------------+-------------+
| image/x-jng | .jng |
+----------------------------------------------------------------------------------+-------------+
| image/jp2 | .jp2 |
+----------------------------------------------------------------------------------+-------------+
| image/jpeg | .jpeg |
+----------------------------------------------------------------------------------+-------------+
| image/jpm | .jpm |
+----------------------------------------------------------------------------------+-------------+
| application/json | .json |
+----------------------------------------------------------------------------------+-------------+
| chemical/x-mopac-input | .mop |
+----------------------------------------------------------------------------------+-------------+
| image/x-nikon-nef | .nef |
+----------------------------------------------------------------------------------+-------------+
| image/x-olympus-orf | .orf |
+----------------------------------------------------------------------------------+-------------+
| application/font-sfnt | .otf |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-bitmap | .pbm |
+----------------------------------------------------------------------------------+-------------+
| image/pcx | .pcx |
+----------------------------------------------------------------------------------+-------------+
| chemical/x-pdb | .pdb |
+----------------------------------------------------------------------------------+-------------+
| application/pdf | .pdf |
+----------------------------------------------------------------------------------+-------------+
| application/x-font | .pfa |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-graymap | .pgm |
+----------------------------------------------------------------------------------+-------------+
| image/png | .png |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-anymap | .pnm |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-pixmap | .ppm |
+----------------------------------------------------------------------------------+-------------+
| image/x-photoshop | .psd |
+----------------------------------------------------------------------------------+-------------+
| image/x-cmu-raster | .ras |
+----------------------------------------------------------------------------------+-------------+
| image/x-rgb | .rgb |
+----------------------------------------------------------------------------------+-------------+
| application/x-silverlight | .scr |
+----------------------------------------------------------------------------------+-------------+
| text/scriptlet | .sct |
+----------------------------------------------------------------------------------+-------------+
| image/tiff | .tiff |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.visio | .vsd |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.wap.wbmp | .wbmp |
+----------------------------------------------------------------------------------+-------------+
| image/x-xbitmap | .xbm |
+----------------------------------------------------------------------------------+-------------+
| application/x-xcf | .xcf |
+----------------------------------------------------------------------------------+-------------+
| image/x-xpixmap | .xpm |
+----------------------------------------------------------------------------------+-------------+
| image/x-xwindowdump | .xwd |
+----------------------------------------------------------------------------------+-------------+
| **Bitmap images - based on Pillow** |
+----------------------------------------------------------------------------------+-------------+
| image/png | .png |
+----------------------------------------------------------------------------------+-------------+
| application/postscript | .ps |
+----------------------------------------------------------------------------------+-------------+
| image/x-eps | - |
+----------------------------------------------------------------------------------+-------------+
| **Images - based on convert command (Image magick)** |
+----------------------------------------------------------------------------------+-------------+
| application/postscript | .ps |
+----------------------------------------------------------------------------------+-------------+
| image/x-jg | .art |
+----------------------------------------------------------------------------------+-------------+
| image/x-ms-bmp | .bmp |
+----------------------------------------------------------------------------------+-------------+
| text/plain | .ksh |
+----------------------------------------------------------------------------------+-------------+
| image/x-canon-cr2 | .cr2 |
+----------------------------------------------------------------------------------+-------------+
| image/x-canon-crw | .crw |
+----------------------------------------------------------------------------------+-------------+
| application/dicom | .dcm |
+----------------------------------------------------------------------------------+-------------+
| application/x-director | .dcr |
+----------------------------------------------------------------------------------+-------------+
| image/x-epson-erf | .erf |
+----------------------------------------------------------------------------------+-------------+
| image/gif | .gif |
+----------------------------------------------------------------------------------+-------------+
| text/x-chdr | .h |
+----------------------------------------------------------------------------------+-------------+
| text/html | .htm |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.microsoft.icon | .ico |
+----------------------------------------------------------------------------------+-------------+
| application/x-info | .info |
+----------------------------------------------------------------------------------+-------------+
| image/x-jng | .jng |
+----------------------------------------------------------------------------------+-------------+
| image/jp2 | .jp2 |
+----------------------------------------------------------------------------------+-------------+
| image/jpeg | .jpeg |
+----------------------------------------------------------------------------------+-------------+
| image/jpm | .jpm |
+----------------------------------------------------------------------------------+-------------+
| application/json | .json |
+----------------------------------------------------------------------------------+-------------+
| chemical/x-mopac-input | .mop |
+----------------------------------------------------------------------------------+-------------+
| image/x-nikon-nef | .nef |
+----------------------------------------------------------------------------------+-------------+
| image/x-olympus-orf | .orf |
+----------------------------------------------------------------------------------+-------------+
| application/font-sfnt | .otf |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-bitmap | .pbm |
+----------------------------------------------------------------------------------+-------------+
| image/pcx | .pcx |
+----------------------------------------------------------------------------------+-------------+
| chemical/x-pdb | .pdb |
+----------------------------------------------------------------------------------+-------------+
| application/pdf | .pdf |
+----------------------------------------------------------------------------------+-------------+
| application/x-font | .pfa |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-graymap | .pgm |
+----------------------------------------------------------------------------------+-------------+
| image/png | .png |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-anymap | .pnm |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-pixmap | .ppm |
+----------------------------------------------------------------------------------+-------------+
| image/x-photoshop | .psd |
+----------------------------------------------------------------------------------+-------------+
| image/x-cmu-raster | .ras |
+----------------------------------------------------------------------------------+-------------+
| image/x-rgb | .rgb |
+----------------------------------------------------------------------------------+-------------+
| application/x-silverlight | .scr |
+----------------------------------------------------------------------------------+-------------+
| text/scriptlet | .sct |
+----------------------------------------------------------------------------------+-------------+
| image/tiff | .tiff |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.visio | .vsd |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.wap.wbmp | .wbmp |
+----------------------------------------------------------------------------------+-------------+
| image/x-xbitmap | .xbm |
+----------------------------------------------------------------------------------+-------------+
| application/x-xcf | .xcf |
+----------------------------------------------------------------------------------+-------------+
| image/x-xpixmap | .xpm |
+----------------------------------------------------------------------------------+-------------+
| image/x-xwindowdump | .xwd |
+----------------------------------------------------------------------------------+-------------+
| **Archive files** |
+----------------------------------------------------------------------------------+-------------+
| application/x-compressed | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-zip-compressed | - |
+----------------------------------------------------------------------------------+-------------+
| application/zip | .zip |
+----------------------------------------------------------------------------------+-------------+
| multipart/x-zip | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-tar | .tar |
+----------------------------------------------------------------------------------+-------------+
| application/x-gzip | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-gtar | .gtar |
+----------------------------------------------------------------------------------+-------------+
| application/x-tgz | - |
+----------------------------------------------------------------------------------+-------------+
| **Vector images - based on Inkscape** |
+----------------------------------------------------------------------------------+-------------+
| image/svg+xml | .svg |
+----------------------------------------------------------------------------------+-------------+
| **Documents - based on LibreOffice** |
+----------------------------------------------------------------------------------+-------------+
| image/wmf | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-hwp | .hwp |
+----------------------------------------------------------------------------------+-------------+
| application/x-aportisdoc | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.chart | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-excel.sheet.binary.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/docbook+xml | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.writer.global | .sxg |
+----------------------------------------------------------------------------------+-------------+
| image/x-xpixmap | .xpm |
+----------------------------------------------------------------------------------+-------------+
| application/x-gnumeric | .gnumeric |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.apple.pages | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-emf | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.stardivision.calc | .sdc |
+----------------------------------------------------------------------------------+-------------+
| text/spreadsheet | - |
+----------------------------------------------------------------------------------+-------------+
| application/mathml+xml | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-sgf | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-sony-bbeb | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-graymap | .pgm |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.doc | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-starwriter | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.spreadsheet | .ods |
+----------------------------------------------------------------------------------+-------------+
| application/clarisworks | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.impress | .sxi |
+----------------------------------------------------------------------------------+-------------+
| application/x-iwork-numbers-sffnumbers | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-powerpoint.slide.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text-master | .odm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.writer.template | .stw |
+----------------------------------------------------------------------------------+-------------+
| application/x-iwork-pages-sffpages | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-iwork-keynote-sffkey | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.graphics-flat-xml | .fodg |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.presentationml.slideshow | .ppsx |
+----------------------------------------------------------------------------------+-------------+
| application/x-abiword | .abw |
+----------------------------------------------------------------------------------+-------------+
| image/x-targa | - |
+----------------------------------------------------------------------------------+-------------+
| application/xhtml+xml | .xhtml |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-excel | .xls |
+----------------------------------------------------------------------------------+-------------+
| image/x-photo-cd | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.stardivision.draw | .sda |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-bitmap | .pbm |
+----------------------------------------------------------------------------------+-------------+
| application/visio.drawing | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.graphics | .odg |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.adobe.photoshop | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.calc.template | .stc |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.lotus-1-2-3 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.writer.web | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.database | - |
+----------------------------------------------------------------------------------+-------------+
| image/cgm | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.math | .sxm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.presentationml.template | .potx |
+----------------------------------------------------------------------------------+-------------+
| application/rtf | .rtf |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.apple.keynote | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-wpg | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-excel.template.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-pagemaker | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-powerpoint | .ppt |
+----------------------------------------------------------------------------------+-------------+
| application/x-mspublisher | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.visio | .vsd |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.presentation | .odp |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.writer | .sxw |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.ppt | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.calc | .sxc |
+----------------------------------------------------------------------------------+-------------+
| image/x-pict | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.impress.template | .sti |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.pptx | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-sun-raster | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-freehand | - |
+----------------------------------------------------------------------------------+-------------+
| application/prs.plucker | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-pocket-word | - |
+----------------------------------------------------------------------------------+-------------+
| text/csv | .csv |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.presentationml.presentation | .pptx |
+----------------------------------------------------------------------------------+-------------+
| image/x-wmf | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.draw | .sxd |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.presentation-flat-xml | .fodp |
+----------------------------------------------------------------------------------+-------------+
| text/html | .htm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.graphics-template | .otg |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.spreadsheet-flat-xml | .fods |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.corel-draw | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-qpro | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-excel.sheet.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.visio.xml | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-pcx | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-svm | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-word.template.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.chart | .odc |
+----------------------------------------------------------------------------------+-------------+
| application/x-fictionbook+xml | - |
+----------------------------------------------------------------------------------+-------------+
| application/msword | .dot |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text | .odt |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-works | - |
+----------------------------------------------------------------------------------+-------------+
| image/vnd.dxf | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text-web | .oth |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.wordprocessingml.template | .dotx |
+----------------------------------------------------------------------------------+-------------+
| image/x-eps | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.stardivision.writer | .sdw |
+----------------------------------------------------------------------------------+-------------+
| text/rtf | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.formula | .odf |
+----------------------------------------------------------------------------------+-------------+
| application/x-stardraw | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | .xlsx |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-powerpoint.presentation.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/wordperfect5.1 | - |
+----------------------------------------------------------------------------------+-------------+
| image/emf | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-starcalc | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text-master-template | .otm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text-template | .ott |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.palm | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.base | - |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.docx | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-t602 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.wordprocessingml.document | .docx |
+----------------------------------------------------------------------------------+-------------+
| image/x-xbitmap | .xbm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.formula-template | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.presentation-template | .otp |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.chart-template | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-met | - |
+----------------------------------------------------------------------------------+-------------+
| application/macwriteii | - |
+----------------------------------------------------------------------------------+-------------+
| application/x-dbase | - |
+----------------------------------------------------------------------------------+-------------+
| image/tiff | .tiff |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.spreadsheet-template | .ots |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.draw.template | .std |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.xls | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.wordperfect | .wpd |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-powerpoint.slideshow.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.spreadsheetml.template | .xltx |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.openxmlformats-officedocument.presentationml.slide | .sldx |
+----------------------------------------------------------------------------------+-------------+
| image/x-portable-pixmap | .ppm |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.visio2013 | - |
+----------------------------------------------------------------------------------+-------------+
| image/x-cmx | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.sun.xml.base | .odb |
+----------------------------------------------------------------------------------+-------------+
| application/wps-office.xlsx | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.oasis.opendocument.text-flat-xml | .fodt |
+----------------------------------------------------------------------------------+-------------+
| image/x-cmu-raster | .ras |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.apple.numbers | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-powerpoint.template.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| image/tif | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.lotus-wordpro | - |
+----------------------------------------------------------------------------------+-------------+
| application/vnd.ms-word.document.macroEnabled.12 | - |
+----------------------------------------------------------------------------------+-------------+
| **Plain text files** |
+----------------------------------------------------------------------------------+-------------+
| text/plain | .ksh |
+----------------------------------------------------------------------------------+-------------+
| text/html | .htm |
+----------------------------------------------------------------------------------+-------------+
| application/xml | .xsl |
+----------------------------------------------------------------------------------+-------------+
| application/javascript | .js |
+----------------------------------------------------------------------------------+-------------+
| **PDF documents - based on PyPDF2** |
+----------------------------------------------------------------------------------+-------------+
| application/pdf | .pdf |
+----------------------------------------------------------------------------------+-------------+

------------
Installation
------------

``pip install preview-generator``


Note about requirements: some packages are needed for installing python. If the ``pip install preview-generator`` command fails, try to install zlib and libjpeg dev packages. On debian-based OSes this can be done through the following command:

``apt-get install zlib1g-dev libjpeg-dev``

This package uses the following python dependencies (this list is not exhaustive): wand, python-magick, pillow, PyPDF2.

Note: if you want to preview office files, ensure that LibreOffice is installed on your computer.

-----
Usage
-----

Here are some examples of code

Generate a thumbnail of an image file
-------------------------------------

.. code:: python

from preview_generator.manager import PreviewManager
manager = PreviewManager('/tmp/cache/', create_folder= True)
thumbnail_file_path = manager.get_jpeg_preview('/home/user/Pictures/myfile.gif', height=100, width=200)
print('Preview created at path : ', thumbnail_file_path)


Generate a pdf preview of a libreoffice text document
-----------------------------------------------------

.. code:: python

from preview_generator.manager import PreviewManager
manager = PreviewManager('/tmp/cache/', create_folder= True)
pdf_file_path = manager.get_pdf_preview('/home/user/Documents/report.odt', page=2)
print('Preview created at path : ', thumbnail_file_path)



The preview manager
-------------------

.. code:: python

preview_manager = PreviewManager(cache_path)

*args :*

*cache_path : a String of the path to the directory where the cache file will be stored*
*create_folder : a boolean, when True will TRY to create the cache folder*

*returns :*

*a PreviewManager Object*

The builders
------------

Here is the way it is meant to be used assuming that cache_path is an existing directory

For Office types into PDF :
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code:: python

preview_manager = PreviewManager(cache_path)
preview = preview_manager.get_pdf_preview(file_path,page=page_id)

-> Will create a preview from an office file into a pdf file

*args :*

*file_path : the String of the path where is the file you want to get the preview*

*page : the int of the page you want to get. If not mentioned all the pages will be returned. First page is page 0*

*use_original_filename : a boolean that mention if the original file name should appear in the preview name. True by default*

*returns :*

*a FileIO stream of bytes of the pdf preview*

For images(GIF, BMP, PNG, JPEG, PDF) into jpeg :
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code:: python

preview_manager = PreviewManager(cache_path)
preview = preview_manager.get_jpeg_preview(file_path,height=1024,width=526)

-> Will create a preview from an image file into a jpeg file of size 1024 * 526

*args :*

*file_path : the String of the path where is the file you want to get the preview*

*height : height of the preview in pixels*

*width : width of the preview in pixels. If not mentioned, width will be the same as height*

*use_original_filename : a boolean that mention if the original file name should appear in the preview name. True by default*

*returns :*

*a FileIO stream of bytes of the jpeg preview*

Other conversions :
~~~~~~~~~~~~~~~~~~~

The principle is the same as above

**Zip to text or html :** will build a list of files into texte/html inside the json

**Office to jpeg :** will build the pdf out of the office file and then build the jpeg.

**Text to text :** mainly just a copy stored in the cache


---------------
Cache mechanism
---------------


Naming :
--------

The name of the preview generated in the cache directory will be :

{file_name}-[{size}-]{file_md5sum}[({page})]{extension}
file_name = the name of the file you asked for a preview without the extension.

size = the size you asked for the preview. In case of a Jpeg preview.

file_md5sum = the md5sum of the entire path of the file. To avoid conflicts like files that have the same name but are in different directory.

page = the page asked in case of pdf or office document preview.

extensions = the extension of the preview (.jpeg for a jpeg, .txt for a text, etc)


Example :
---------

These scripts :

GIF to JPEG :
~~~~~~~~~~~~~


.. code:: python

import os
from preview-generator.manager import PreviewManager
current_dir = os.path.dirname(os.path.abspath(__file__)) +'/'

manager = PreviewManager(path=current_dir + 'cache')
path_to_file = manager.get_jpeg_preview(
file_path=current_dir + 'the_gif.gif',
height=512,
width=512,
)

print('Preview created at path : ', path_to_file)

will print

Preview created at path : the_gif-512x512-60dc9ef46936cc4fff2fe60bb07d4260.jpeg

ODT to JPEG :
~~~~~~~~~~~~~

.. code:: python

import os
from preview-generator.manager import PreviewManager
current_dir = os.path.dirname(os.path.abspath(__file__)) +'/'

manager = PreviewManager(path=current_dir + 'cache')
path_to_file = manager.get_jpeg_preview(
file_path=current_dir + 'the_odt.odt',
page=1,
height=1024,
width=1024,
)

print('Preview created at path : ', path_to_file)

will print

Preview created at path : the_odt-1024x1024-c8b37debbc45fa96466e5e1382f6bd2e-page1.jpeg

ZIP to Text :
~~~~~~~~~~~~~
.. code:: python

import os
from preview-generator.manager import PreviewManager
current_dir = os.path.dirname(os.path.abspath(__file__)) +'/'

manager = PreviewManager(path=current_dir + 'cache')
path_to_file = manager.get_text_preview(
file_path=current_dir + 'the_zip.zip',
)

print('Preview created at path : ', path_to_file)

will print

Preview created at path : the_zip-a733739af8006558720be26c4dc5569a.txt


--------------------
Adding new feature :
--------------------

Before all, I'd be glad if you could share your new feature with everybody. So if you want to, you can fork it on github ( https://github.com/algoo/preview-generator) (see `Developer’s Kit`_) and submit new features.

If you want to add a new preview builder to handle documents of type **foo** into **jpeg** (for example) here is how to proceed :

- **Warning** If you need to look at other builders to find out how to proceed, avoid looking at any of the Office to something. It is a particular case and could misslead you.
- Create a new class FooPreviewBuilder in a file foo_preview.py in preview-generator/preview
- Make him inherit from the logical PreviewBuilder class

* if it handles several pages it will be `class FooPreviewBuilder(PreviewBuilder)`
* for single page it will be `class FooPreviewBuilder(OnePagePreviewBuilder)`
* ...
- define your own `build_jpeg_preview(...)` (in the case we want to make **foo** into **jpeg**) based on the same principle as other build_{type}_preview(...)
- Inside this build_jpeg_preview(...) you will call a method file_converter.foo_to_jpeg(...)
- Define your foo_to_jpeg(...) method in preview-generator.file_converter.py

* inputs must be a stream of bytes and optional informations like a number of pages, a size, ...
* output must also be a stream of bytes
- Maybe you'll need to redefine some methods like `get_page_number()` or `exists_preview()` in your FooPreviewBuilder class


---------------
Developer’s Kit
---------------


Installation (dev) :
--------------------


From scratch on a terminal :
- create your project directory (we will name it "the_project" but you can name it the way you want) : `mkdir the_project`
- `cd the_project`
- `git clone https://github.com/algoo/preview-generator`
- building your environment :
* install python virtualenv builder : `sudo apt install python3-venv`
* build your virtual env (I can say that it work with python 3.4 but did not try with other versions)(env will be called "myenv", you can name it the way you want): `python3.4 -m venv myenv`
* if it's not already, activate it : `source myenv/bin/activate`. (`deactivate` to deactivate)
- install dependencies :

* Exiftool - Follow instruction on the main website: https://sno.phy.queensu.ca/~phil/exiftool/
* `apt-get install zlib1g-dev`
* `apt-get install libjpeg-dev`
* `apt-get install python3-pythonmagick`
* `apt-get install inkscape`
* `apt-get install xvfb`
* `apt-get install poppler-utils`
* `pip install wand`
* `pip install Pillow`
* `pip install PyPDF2`
* `pip install python-magic`
* `pip install pyexifinfo`
* `pip install packaging`
* `pip install xvfbwrapper`
* `pip install pdf2image`
* `pip install pathlib`
* if you use python 3.5 or less `pip install typing`


.. code:: console

# general dependencies
apt-get install libjpeg-dev libjpeg-dev python3-pythonmagick inkscape xvfb
pip install wand Pillow PyPDF2 python-magic pyexifinfo packaging xvfbwrapper pdf2image pathlib
# Exiftool
wget https://sno.phy.queensu.ca/~phil/exiftool/Image-ExifTool-11.11.tar.gz
gzip -dc Image-ExifTool-11.11.tar.gz | tar -xf -
cd Image-ExifTool-11.11
perl Makefile.PL
sudo make install

If you need to preview scribus `.sla` files you will need scribus >= 1.5.
If it's not available in your distribution you can use an AppImage.

Download the last AppImage from the official website https://www.scribus.net/downloads/unstable-branch/

.. code:: console

mv /path/to/image/scribus-x.y.appimage /usr/local/bin/scribus
chmod +x /usr/local/bin/scribus



Running Pytest :
----------------
Pytest is a motor for unit testing

* `pip install pytest`
* go into the "tests" directory : `cd path/to/you/project/directory/tests`
* run `py.test`

------------
License
------------

MIT licensed. https://opensource.org/licenses/MIT

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