316 lines
9.8 KiB
Python
316 lines
9.8 KiB
Python
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# Copyright 2014 Google Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Schema processing for discovery based APIs
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Schemas holds an APIs discovery schemas. It can return those schema as
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deserialized JSON objects, or pretty print them as prototype objects that
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conform to the schema.
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For example, given the schema:
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schema = \"\"\"{
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"Foo": {
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"type": "object",
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"properties": {
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"etag": {
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"type": "string",
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"description": "ETag of the collection."
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},
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"kind": {
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"type": "string",
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"description": "Type of the collection ('calendar#acl').",
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"default": "calendar#acl"
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},
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"nextPageToken": {
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"type": "string",
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"description": "Token used to access the next
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page of this result. Omitted if no further results are available."
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}
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}
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}
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}\"\"\"
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s = Schemas(schema)
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print s.prettyPrintByName('Foo')
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Produces the following output:
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{
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"nextPageToken": "A String", # Token used to access the
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# next page of this result. Omitted if no further results are available.
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"kind": "A String", # Type of the collection ('calendar#acl').
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"etag": "A String", # ETag of the collection.
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},
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The constructor takes a discovery document in which to look up named schema.
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"""
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from __future__ import absolute_import
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import six
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# TODO(jcgregorio) support format, enum, minimum, maximum
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__author__ = "jcgregorio@google.com (Joe Gregorio)"
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import copy
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from googleapiclient import _helpers as util
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class Schemas(object):
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"""Schemas for an API."""
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def __init__(self, discovery):
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"""Constructor.
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Args:
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discovery: object, Deserialized discovery document from which we pull
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out the named schema.
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"""
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self.schemas = discovery.get("schemas", {})
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# Cache of pretty printed schemas.
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self.pretty = {}
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@util.positional(2)
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def _prettyPrintByName(self, name, seen=None, dent=0):
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"""Get pretty printed object prototype from the schema name.
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Args:
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name: string, Name of schema in the discovery document.
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seen: list of string, Names of schema already seen. Used to handle
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recursive definitions.
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Returns:
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string, A string that contains a prototype object with
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comments that conforms to the given schema.
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"""
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if seen is None:
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seen = []
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if name in seen:
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# Do not fall into an infinite loop over recursive definitions.
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return "# Object with schema name: %s" % name
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seen.append(name)
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if name not in self.pretty:
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self.pretty[name] = _SchemaToStruct(
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self.schemas[name], seen, dent=dent
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).to_str(self._prettyPrintByName)
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seen.pop()
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return self.pretty[name]
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def prettyPrintByName(self, name):
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"""Get pretty printed object prototype from the schema name.
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Args:
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name: string, Name of schema in the discovery document.
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Returns:
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string, A string that contains a prototype object with
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comments that conforms to the given schema.
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"""
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# Return with trailing comma and newline removed.
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return self._prettyPrintByName(name, seen=[], dent=1)[:-2]
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@util.positional(2)
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def _prettyPrintSchema(self, schema, seen=None, dent=0):
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"""Get pretty printed object prototype of schema.
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Args:
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schema: object, Parsed JSON schema.
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seen: list of string, Names of schema already seen. Used to handle
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recursive definitions.
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Returns:
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string, A string that contains a prototype object with
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comments that conforms to the given schema.
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"""
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if seen is None:
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seen = []
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return _SchemaToStruct(schema, seen, dent=dent).to_str(self._prettyPrintByName)
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def prettyPrintSchema(self, schema):
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"""Get pretty printed object prototype of schema.
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Args:
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schema: object, Parsed JSON schema.
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Returns:
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string, A string that contains a prototype object with
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comments that conforms to the given schema.
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"""
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# Return with trailing comma and newline removed.
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return self._prettyPrintSchema(schema, dent=1)[:-2]
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def get(self, name, default=None):
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"""Get deserialized JSON schema from the schema name.
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Args:
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name: string, Schema name.
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default: object, return value if name not found.
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"""
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return self.schemas.get(name, default)
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class _SchemaToStruct(object):
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"""Convert schema to a prototype object."""
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@util.positional(3)
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def __init__(self, schema, seen, dent=0):
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"""Constructor.
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Args:
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schema: object, Parsed JSON schema.
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seen: list, List of names of schema already seen while parsing. Used to
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handle recursive definitions.
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dent: int, Initial indentation depth.
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"""
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# The result of this parsing kept as list of strings.
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self.value = []
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# The final value of the parsing.
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self.string = None
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# The parsed JSON schema.
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self.schema = schema
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# Indentation level.
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self.dent = dent
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# Method that when called returns a prototype object for the schema with
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# the given name.
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self.from_cache = None
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# List of names of schema already seen while parsing.
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self.seen = seen
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def emit(self, text):
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"""Add text as a line to the output.
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Args:
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text: string, Text to output.
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"""
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self.value.extend([" " * self.dent, text, "\n"])
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def emitBegin(self, text):
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"""Add text to the output, but with no line terminator.
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Args:
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text: string, Text to output.
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"""
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self.value.extend([" " * self.dent, text])
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def emitEnd(self, text, comment):
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"""Add text and comment to the output with line terminator.
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Args:
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text: string, Text to output.
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comment: string, Python comment.
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"""
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if comment:
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divider = "\n" + " " * (self.dent + 2) + "# "
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lines = comment.splitlines()
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lines = [x.rstrip() for x in lines]
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comment = divider.join(lines)
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self.value.extend([text, " # ", comment, "\n"])
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else:
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self.value.extend([text, "\n"])
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def indent(self):
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"""Increase indentation level."""
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self.dent += 1
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def undent(self):
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"""Decrease indentation level."""
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self.dent -= 1
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def _to_str_impl(self, schema):
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"""Prototype object based on the schema, in Python code with comments.
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Args:
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schema: object, Parsed JSON schema file.
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Returns:
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Prototype object based on the schema, in Python code with comments.
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"""
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stype = schema.get("type")
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if stype == "object":
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self.emitEnd("{", schema.get("description", ""))
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self.indent()
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if "properties" in schema:
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for pname, pschema in six.iteritems(schema.get("properties", {})):
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self.emitBegin('"%s": ' % pname)
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self._to_str_impl(pschema)
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elif "additionalProperties" in schema:
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self.emitBegin('"a_key": ')
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self._to_str_impl(schema["additionalProperties"])
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self.undent()
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self.emit("},")
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elif "$ref" in schema:
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schemaName = schema["$ref"]
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description = schema.get("description", "")
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s = self.from_cache(schemaName, seen=self.seen)
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parts = s.splitlines()
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self.emitEnd(parts[0], description)
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for line in parts[1:]:
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self.emit(line.rstrip())
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elif stype == "boolean":
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value = schema.get("default", "True or False")
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self.emitEnd("%s," % str(value), schema.get("description", ""))
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elif stype == "string":
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value = schema.get("default", "A String")
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self.emitEnd('"%s",' % str(value), schema.get("description", ""))
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elif stype == "integer":
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value = schema.get("default", "42")
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self.emitEnd("%s," % str(value), schema.get("description", ""))
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elif stype == "number":
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value = schema.get("default", "3.14")
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self.emitEnd("%s," % str(value), schema.get("description", ""))
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elif stype == "null":
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self.emitEnd("None,", schema.get("description", ""))
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elif stype == "any":
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self.emitEnd('"",', schema.get("description", ""))
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elif stype == "array":
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self.emitEnd("[", schema.get("description"))
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self.indent()
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self.emitBegin("")
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self._to_str_impl(schema["items"])
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self.undent()
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self.emit("],")
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else:
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self.emit("Unknown type! %s" % stype)
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self.emitEnd("", "")
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self.string = "".join(self.value)
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return self.string
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def to_str(self, from_cache):
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"""Prototype object based on the schema, in Python code with comments.
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Args:
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from_cache: callable(name, seen), Callable that retrieves an object
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prototype for a schema with the given name. Seen is a list of schema
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names already seen as we recursively descend the schema definition.
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Returns:
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Prototype object based on the schema, in Python code with comments.
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The lines of the code will all be properly indented.
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"""
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self.from_cache = from_cache
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return self._to_str_impl(self.schema)
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