dicta 0.8.14

A dict subclass to observe data changes in the nested data-tree.

dicta

A dict subclass that observes a nested dict and listens for changes in its data structure. If a data change is registered, Dicta reacts with a callback or a data-export to a JSON file.

Core Functionality

• Throw a callback, when the nested data structure changes
• Write data to a JSON file, when the nested data structure changes

Features

• Behaves like a regular dict and supports all dict, list, tuple and set methods.
• Supports nesting of all possible datatypes like dict, list, tuple, set and other objects like custom classes.
• Encodes non-serializable objects to a binary-string when writing data to a file (Optional / deactivated by default).
• Reading data from a file will decode a binary-string back to a non-serializable object (Optional / deactivated by default).
• Import/Insert additional data from json files.
• Export data to json files.

Install

pip3 install dicta

How to use

import dicta

# Declare the 'Dicta' class.
dicta = dicta.Dicta()

# Activate binary serialization
dicta.setBinarySerializer(True)

# Set a synch file path.
dicta.synchFile("data.json")

# Define the callback method
def callback():
    print("Data changed!")
    print(dicta)

# Bind the callback method to dicta
dicta.bind(callback)

# Add data
dicta["entities"] = {}
dicta["entities"]["persons"] = []

dicta["entities"]["persons"].append({"name":"john", "age":23})
dicta["entities"]["persons"].append({"name":"peter", "age":13})

# Update a key in a dict
dicta["entities"]["persons"][1]["age"] = 42

# Add another nested list to the dict
dicta["entities"]["animals"] = []
dicta["entities"]["animals"].append("lion")
dicta["entities"]["animals"].append("elephant")

# Slice item from list
del dicta["entities"]["animals"][0:1]

# Remove item from dict
dicta["entities"].pop("persons")

# and so forth…
# Should support all regular dict behaviours and 
# list methods (pop(), append(), slice(), insert() …)

# Import additional data from another file. 
# (New data will be added. Old data remains but will 
# be overwritten if dict keys match.)
dicta.insert("additional_data_file.json")

# Export the data to another file
dicta.export("data_backup.json")

# Get string representation of the Dicta
dicta.stringify()

Reference

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Dicta()

Dicta(*args, **kwargs)

A dict subclass.

Parameter

• *args (Optional)
• **kwargs (Optional)

Return

• Dicta Class

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Methods

Dicta Methods

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Dicta.bind()

Dicta.bind(callback, response=False, *args, *kwargs)

Sets the callback method for the Dicta Class. If response=False (default) the callback method only gets the *args, *kwargs as parameters you define. If response=True the callback method gets response from the Dicta Class. You should define your callback function with a *kwargs parameter or with three positional parameters:

def my_callback(**kwargs)

or

def my_callback(modifed_object, modify_info, modify_trace)

Parameter

• callback (method)
• default_response (bool) (optional / default = False)

Callback

• args as defined in setCallback (optional / default: None)
• kwargs as defined in setCallback (optional / default: None)
• modifed_object (object)
• modify_info (json_string): Contains info about the data mod
• modify_trace (list): Contains the dict-tree-path to the modified object as a list starting from root*

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Dicta.syncFile()

Dicta.syncFile(path, reset=False)

Sets the sync file to automatically store the data on data change. If reset=False (default) old data will remain and will be updated with new data . If reset=True the data wil be cleared when syncFile() is called.

This will fail if your dict contains non-serializable objects and binary serialization is not activated. For security reasons this is deactivated by default. You can activate binary serialization manually with Dicta.useBinarySerializer(True).

If you activate the binary-serializer all non-serializable objects will be encoded to a binary string and packed into a dict labeled with the key '<serialized-object>'. See the reference for Dicta.useBinarySerializer().

Parameter

• path (string)
• reset (bool) (optional / default = False)

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Dicta.importFile()

Dicta.importFile(path)

Import data from a file. New data will be added to the DictObsercer, old data remains but will be overwritten if dict keys match.

Parameter

• path (string)

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Dicta.exportFile()

Dicta.exportFile(path, reset=True)

Export data to a file. If reset=True the data wil be cleared when exportFile() (default) is called . If reset=False the data will be updated.

This will fail if your dict contains non-serializable objects and binary serialization is not activated. For security reasons this is deactivated by default. You can activate binary serialization by calling Dicta.useBinarySerializer(True) before.

If you activate the binary-serializer all non-serializable objects will be encoded to a binary string and packed into a dict labeled with the key '<serialized-object>'. See the reference for Dicta.useBinarySerializer().

Parameter

• path (string)
• reset (bool) (optional / default = True)

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Dicta.clearFile()

Dicta.clearFile(path)

Clear a file.

Parameter

• path (string)

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Dicta.removeFile()

Dicta.removeFile(path)

Remove a data file.

Parameter

• path (string)

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Dicta.dictify()

Dicta.dictify()

Returns a plain dict representation of the data without Dicta functionality.

Parameter

• None

Return

• dict

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Dicta.stringify()

Dicta.stringify(returnBinaries=False)

Returns a string representation of the data in Dicta.

This will fail if your dict contains non-serializable objects and binary serialization is not activated. For security reasons this is deactivated by default. You can activate binary serialization by calling Dicta.useBinarySerializer(True) before.

If you activate the binary-serializer all non-serializable objects will be encoded to a binary string and packed into a dict labeled with the key '<serialized-object>'. See the reference for Dicta.useBinarySerializer().

For better readability serialized objects won´t be returned by default and are replaced by a the '<serialized-object>' hook. If you want to return the binaries set the return_binariesparameter to True.

Parameter

• return_binaries (bool) (default = False)

Return

• string

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Dicta.setBinarySerializer()

Dicta.setBinarySerializer(binary_serializer=False, serializer_hook='<serialized-object>')

For security reasons binary serialization of non-serializable objects is deactivated by default. You can activate or deactivate binary serialization with this method (default=False).

If you activate the binary-serializer all non-serializable objects will be encoded to a binary string and packed into a dict labeled with the key '<serialized-object>'. In case you need this key for your data structure, define a custom serializer-hook by using the serializer_hook parameter (optional). If you don´t use the serializer_hook parameter the default hook '<serialized-object>' will be used.

Parameter

• use_binary_serializer (bool) (default = False)
• serializer_hook (string) (optional / default = '<serialized-object>')

Example

myDictObserver.useBinarySerializer(True, '<my_serialzer_hook>')

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Data Type Methods

Behaves like a regular nested dict and supports all data type methods. Adding, removing, modifiying and accessing of nested elements should work out of the box. For example:

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NestedDict.update()

NestedDict.update(*args, *kwargs)

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NestedDict.clear()

NestedDict.clear()

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NestedDict.pop()

NestedDict.pop(key)

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NestedDict.popitem()

NestedDict.popitem(key)

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NestedDict.setdefault()

NestedDict.setdefault(key, default=None)

and so forth: keys(), iter() …

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NestedList.append()

NestedList.append(item)

and so forth: pop()…

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Dependencies

• os
• re
• json
• pickle