Metadata-Version: 1.1
Name: jsonmerge
Version: 1.1.0
Summary: Merge a series of JSON documents.
Home-page: UNKNOWN
Author: Tomaz Solc
Author-email: tomaz.solc@tablix.org
License: MIT
Description: Merge a series of JSON documents
        ================================
        
        This Python module allows you to merge a series of JSON documents into a
        single one.
        
        This problem often occurs for example when different authors fill in
        different parts of a common document and you need to construct a document
        that includes contributions from all the authors. It also helps when
        dealing with consecutive versions of a document where different fields get
        updated over time.
        
        Consider a trivial example with two documents::
        
            >>> base = {
            ...         "foo": 1,
            ...         "bar": [ "one" ],
            ...      }
        
            >>> head = {
            ...         "bar": [ "two" ],
            ...         "baz": "Hello, world!"
            ...     }
        
        We call the document we are merging changes into *base* and the changed
        document *head*. To merge these two documents using *jsonmerge*::
        
            >>> from pprint import pprint
        
            >>> from jsonmerge import merge
            >>> result = merge(base, head)
        
            >>> pprint(result, width=40)
            {'bar': ['two'],
             'baz': 'Hello, world!',
             'foo': 1}
        
        As you can see, when encountering an JSON object, *jsonmerge* by default
        returns fields that appear in either *base* or *head* document. For other
        JSON types, it simply replaces the older value. These principles are also
        applied in case of multiple nested JSON objects.
        
        In a more realistic use case however, you might want to apply different
        *merge strategies* to different parts of the document. You can tell
        *jsonmerge* how to do that using a syntax based on `JSON schema`_.
        
        If you already have schemas for your document, you can simply expand them
        with additional keywords recognized by *jsonmerge*.
        
        You use the *mergeStrategy* schema keyword to specify the strategy. The
        default two strategies mentioned above are called *objectMerge* for objects
        and *overwrite* for all other types.
        
        Let's say you want to specify that the merged *bar* field in the example
        document above should contain elements from all documents, not just the
        latest one. You can do this with a schema like this::
        
            >>> schema = {
            ...             "properties": {
            ...                 "bar": {
            ...                     "mergeStrategy": "append"
            ...                 }
            ...             }
            ...         }
        
            >>> from jsonmerge import Merger
            >>> merger = Merger(schema)
            >>> result = merger.merge(base, head)
        
            >>> pprint(result, width=40)
            {'bar': ['one', 'two'],
             'baz': 'Hello, world!',
             'foo': 1}
        
        Another common example is when you need to keep a versioned list of values
        that appeared in the series of documents::
        
            >>> schema = {
            ...             "properties": {
            ...                 "foo": {
            ...                     "type": "object",
            ...                     "mergeStrategy": "version",
            ...                     "mergeOptions": { "limit": 5 }
            ...                 }
            ...             }
            ...         }
            >>> from jsonmerge import Merger
            >>> merger = Merger(schema)
        
            >>> v1 = {
            ...     'foo': {
            ...         'greeting': 'Hello, World!'
            ...     }
            ... }
        
            >>> v2 = {
            ...     'foo': {
            ...         'greeting': 'Howdy, World!'
            ...     }
            ... }
        
            >>> base = None
            >>> base = merger.merge(base, v1, meta={'version': 1})
            >>> base = merger.merge(base, v2, meta={'version': 2})
        
            >>> pprint(base, width=55)
            {'foo': [{'value': {'greeting': 'Hello, World!'},
                      'version': 1},
                     {'value': {'greeting': 'Howdy, World!'},
                      'version': 2}]}
        
        Note that we use the *mergeOptions* keyword to supply additional options to
        the merge strategy. In this case, we tell the *version* strategy to retain
        only 5 most recent versions of this field. We also used the *meta* argument
        to supply some document meta-data that is included for each version of the
        field. *meta* can contain an arbitrary JSON object.
        
        Example above also demonstrates how *jsonmerge* is typically used when
        merging more than two documents. Typically you start with an empty *base*
        and then consecutively merge different *heads* into it.
        
        If you care about well-formedness of your documents, you might also want to
        obtain a schema for the documents that the *merge* method creates.
        *jsonmerge* provides a way to automatically generate it from a schema for
        the input document::
        
            >>> result_schema = merger.get_schema()
        
            >>> pprint(result_schema, width=80)
            {'properties': {'foo': {'items': {'properties': {'value': {'type': 'object'}}},
                                    'maxItems': 5,
                                    'type': 'array'}}}
        
        Note that because of the *version* strategy, the type of the *foo* field
        changed from *object* to *array*.
        
        
        Merge strategies
        ----------------
        
        These are the currently implemented merge strategies.
        
        overwrite
          Overwrite with the value in *base* with value in *head*. Works with any
          type.
        
        append
          Append arrays. Works only with arrays.
        
        arrayMergeById
          Merge arrays, identifying items to be merged by an ID field. Resulting
          arrays have items from both *base* and *head* arrays.  Any items that
          have identical an ID are merged based on the strategy specified further
          down in the hierarchy.
        
          By default, array items are expected to be objects and ID of the item is
          obtained from the *id* property of the object.
        
          You can specify an arbitrary *JSON pointer* to point to the ID of the
          item using the *idRef* merge option. When resolving the pointer, document
          root is placed at the root of the array item (e.g. by default, *idRef* is
          '/id')
        
          Array items in *head* for which the ID cannot be identified (e.g. *idRef*
          pointer is invalid) are ignored.
        
          You can specify an additional item ID to be ignored using the *ignoreId*
          merge option.
        
        objectMerge
          Merge objects. Resulting objects have properties from both *base* and
          *head*. Any properties that are present both in *base* and *head* are
          merged based on the strategy specified further down in the hierarchy
          (e.g. in *properties*, *patternProperties* or *additionalProperties*
          schema keywords).
        
        version
          Changes the type of the value to an array. New values are appended to the
          array in the form of an object with a *value* property. This way all
          values seen during the merge are preserved.
        
          You can limit the length of the list using the *limit* option in the
          *mergeOptions* keyword.
        
          By default, if a *head* document contains the same value as the *base*,
          document, no new version will be appended. You can change this by setting
          *ignoreDups* option to *false*.
        
        If a merge strategy is not specified in the schema, *objectMerge* is used
        to objects and *overwrite* for all other values.
        
        You can implement your own strategies by making subclasses of
        jsonmerge.strategies.Strategy and passing them to Merger() constructor.
        
        
        Limitations
        -----------
        
        Merging of documents with schemas that do not have a well-defined type
        (e.g. schemas using *allOf*, *anyOf* and *oneOf*) will likely fail. Such
        documents could require merging of two values of different types. For
        example, *jsonmerge* does not know how to merge a string to an object.
        
        You can work around this limitation by defining for your own strategy that
        defines what to do in such cases. See docstring documentation for the
        *Strategy* class on how to do that. get_schema() however currently provides
        no support for ambiguous schemas like that.
        
        
        Requirements
        ------------
        
        You need *jsonschema* (https://pypi.python.org/pypi/jsonschema) module
        installed.
        
        
        Installation
        ------------
        
        You install *jsonmerge*, as you would install any Python module, by running
        these commands::
        
            python setup.py install
            python setup.py test
        
        
        Source
        ------
        
        The latest version is available on GitHub: https://github.com/avian2/jsonmerge
        
        
        License
        -------
        
        Copyright 2014, Tomaz Solc <tomaz.solc@tablix.org>
        
        Permission is hereby granted, free of charge, to any person obtaining a copy
        of this software and associated documentation files (the "Software"), to deal
        in the Software without restriction, including without limitation the rights
        to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        copies of the Software, and to permit persons to whom the Software is
        furnished to do so, subject to the following conditions:
        
        The above copyright notice and this permission notice shall be included in
        all copies or substantial portions of the Software.
        
        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
        AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        THE SOFTWARE.
        
        .. _JSON schema: http://json-schema.org
        
        ..
            vim: tw=75 ts=4 sw=4 expandtab softtabstop=4
        
Platform: UNKNOWN
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 3
Classifier: Intended Audience :: Developers