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Extract, clean, transform, hyphenate and metadata for ISBNs (International Standard Book Number).

Project description

Graph Documentation Status Coverage Built Status Windows Built Status


isbnlib is a (pure) python library that provides several useful methods and functions to validate, clean, transform, hyphenate and get metadata for ISBN strings. Its origin was as the core of isbntools.

This short version, is suitable to be include as a dependency in other projects. Has a straightforward setup and a very easy programmatic api.

Runs on py26, py27, py33, py34, py35, py36, pypy and pypy3.

Typical usage (as library):

import isbnlib


The official form of an ISBN is something like ISBN 979-10-90636-07-1. However for most applications only the numbers are important, you can always ‘masked’ them if you need (see below). This library works mainly with ‘striped’ ISBNs (only digits and X) like ‘0826497527’. You can strip an ISBN-like string by using canonical(isbnlike). You can ‘mask’ the ISBN by using mask(isbn). So in the examples below, when you see ‘isbn’ in the argument, it is a ‘striped’ ISBN, when the argument is an ‘isbnlike’ it is a string like ISBN 979-10-90636-07-1 or even something dirty like asdf 979-10-90636-07-1 bla bla.

Two important concepts: valid ISBN should be an ISBN that was built according with the rules, this is distinct from issued ISBN that is an ISBN that was already issued to a publisher (this is the usage of the libraries and most of the web services). However, probably by legal reasons, merges the two! So, according to, ‘9786610326266’ is not valid (because the block 978-66… has not been issued yet, however if you use is_isbn13('9786610326266') you will get True (because ‘9786610326266’ follows the rules of an ISBN). But the situation is even murkier, try meta('9786610326266') and you will see that this ISBN was already used!

If possible, work with ISBNs in the isbn-13 format (since 2007, only are issued ISBNs in the isbn-13 format). You can always convert isbn-10 to isbn-13, but not the reverse. Read more about ISBN at or wikipedia.

Main Functions

Validates as ISBN-10.
Validates as ISBN-13.
Transforms isbn-13 to isbn-10.
Transforms isbn-10 to isbn-13.
Keeps only digits and X. You will get strings like 9780321534965 and 954430603X.
Cleans ISBN (only legal characters).
notisbn(isbnlike, level='strict')
Check with the goal to invalidate isbn-like.
get_isbnlike(text, level='normal')
Extracts all substrings that seem like ISBNs (very useful for scraping).
get_canonical_isbn(isbnlike, output='bouth')
Extracts ISBNs and transform them to the canonical form.
Transforms an isbnlike string into an EAN13 number (validated canonical ISBN-13).
Gets the language or country assigned to this ISBN.
mask(isbn, separator='-')
Mask (hyphenate) a canonical ISBN.
meta(isbn, service='default', cache='default')
Gives you the main metadata associated with the ISBN. As service parameter you can use: 'wcat' uses (no key is needed), 'goob' uses the Google Books service (no key is needed), 'isbndb' uses the service (an api key is needed), 'openl' uses the api (no key is needed), merge uses a merged record of wcat and goob records (no key is needed) and is the default option. You can get an API key for the service here. You can enter API keys with config.add_apikey(service, apikey) (see example below). The output can be formatted as bibtex, msword, endnote, refworks, opf or json (BibJSON) bibliographic formats with isbnlib.registry.bibformatters. cache only allows two values: ‘default’ or None. You can change the kind of cache by using isbnlib.registry.set_cache (see below). Now, you can extend the functionality of this function by adding pluggins, more metadata providers or new bibliographic formatters (check for available pluggins).
editions(isbn, service='merge')
Returns the list of ISBNs of editions related with this ISBN. By default uses ‘merge’ (merges ‘openl’ with ‘thingl’), but other providers are available: ‘openl’ users Open Library, ‘thingl’ (uses the service ThingISBN from LibraryThing) and ‘any’ (first tries ‘openl’, if no data, tries ‘thingl’).
Returns the most probable ISBN from a list of words (for your geographic area).
Returns a list of references from Google Books multiple references.
Returns a DOI’s ISBN-A from a ISBN-13.
Returns metadata formated as BibTeX for a given DOI.
Renames a file using metadata from an ISBN in his filename.
Returns a small description of the book. Almost all data available are for US books!
Returns a dictionary with the url for cover. Almost all data available are for US books!

See files test_core and test_ext for a lot of examples.


From the command line, enter (in some cases you have to preced the command with sudo):

$ pip install isbnlib


$ easy_install isbnlib

If you use linux systems, you can install using your distribution package manager (all major distributions have packages python-isbnlib and python3-isbnlib), however (usually) are very old and don’t work well anymore!

For Devs

API’s Main Namespaces

In the namespace isbnlib you have access to the core methods: is_isbn10, is_isbn13, to_isbn10, to_isbn13, canonical, clean, notisbn, get_isbnlike, get_canonical_isbn, mask, meta, info, editions, goom, ren, doi, EAN13, isbn_from_words, desc and cover.

The exceptions raised by these methods can all be catched using ISBNLibException.

You can extend the lib by using the classes and functions exposed in namespace, namely:

  • WEBService a class that handles the access to web services (just by passing an url) and supports gzip. You can subclass it to extend the functionality… but probably you don’t need to use it! It is used in the next class.
  • WEBQuery a class that uses WEBService to retrieve and parse data from a web service. You can build a new provider of metadata by subclassing this class. His main methods allow passing custom functions (handlers) that specialize them to specific needs (data_checker and parser). It implements a throttling mechanism with a default rate of one call per second per service.
  • Metadata a class that structures, cleans and ‘validates’ records of metadata. His method merge allows to implement a simple merging procedure for records from different sources. The main features of this class, can be implemented by a call to the stdmeta function instead!
  • vias exposes several functions to put calls to services, just by passing the name and a pointer to the service’s query function. vias.parallel allows to put threaded calls. You can use vias.serial to make serial calls and vias.multi to use several cores. The default is vias.serial.

The exceptions raised by these methods can all be catched using ISBNLibDevException. You should’t raise this exception in your code, only raise the specific exceptions exposed in whose name end in Error.

In you can find several methods, that we found very useful, some of then are only used in isbntools (an app and framework that uses isbnlib).

With isbnlib.registry you can change the metadata service to be used by default (setdefaultservice), add a new service (add_service), access bibliographic formatters for metadata (bibformatters), set the default formatter (setdefaultbibformatter), add new formatters (add_bibformatter) and set a new cache (set_cache) (e.g. to switch off the chache set_cache(None)). The cache only works for calls through isbnlib.meta. These changes only work for the ‘current session’, so should be done always before calling other methods.

Finally, from isbnlib.config you can read and set configuration options: change timeouts with seturlopentimeout and setthreadstimeout, access api keys with apikeys and add new one with add_apikey and access and set generic and user-defined options with options and set_option.

Let us concretize the last point with a small example.

Suppose you want a small script to get metadata using formated in BibTeX.

To use this service you need an api-key (get it here). A minimal script would be:

from isbnlib import meta
from isbnlib.config import add_apikey
from isbnlib.registry import bibformatters

SERVICE = 'isbndb'
APIKEY = 'THiSIsfAKe'  # <-- replace with YOUR key

# register your key
add_apikey(SERVICE, APIKEY)

# now you can use the service
isbn = '9780446310789'
bibtex = bibformatters['bibtex']
print(bibtex(meta(isbn, SERVICE)))


You can extend the functionality of the library by adding pluggins (for now, just new metadata providers or new bibliographic formatters).

Start with this template and follow the instructions there. For inspiration take a look at wcat, goob or merge.

After install, your pluggin will blend transparently in isbnlib.

Remember that plugins must support python 2.6+ and python 3.3+ (see

Merge Metadata

The original quality of metadata, at the several services, is not very good! If you need high quality metadata in your app, the only solution is to use polling & merge of several providers and a lot of cleaning and standardization for fields like Authors and Publisher.

A merge provider is now the default in meta. It gives priority to wcat but overwrites the Authors field with values from goob (if available). Uses the merge method of Metadata and serial calls to services by default (faster for one-call to services through fast internet connections). You can change that by using vias’s other methods (e.g. isbnlib.config.set_option('VIAS_MERGE', 'multi').


  1. These classes are optimized for one-call to services and not for batch calls. However, is very easy to produce an high volume processing system using these classes (use vias.multi) and Redis.
  2. If you inspect the library, you will see that there are a lot of private modules (their name starts with ‘_’). These modules should not be accessed directly since, with high probability, your program will break with a further version of the library!


If you need help, please take a look at github or post a question on stackoverflow (with tag isbnlib)

Read isbnlib code in a very sctructured way at sourcegraph or ‘the docs’ at readthedocs.

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