Patch 1

ref_resolver/resolver.py

@@ -0,0 +1,159 @@
+from urlparse import urlparse, urljoin
+import simplejson as json
+from os.path import isfile
+import jsonpath_rw
+import requests
+import logging
+
+
+logging.basicConfig(level=logging.DEBUG)
+
+
+def debug(message):
+    logging.debug(message)
+
+
+def info(message):
+    logging.info(message)
+
+cache = {}
+
+
+class IdError(Exception):
+    def __init__(self, value):
+        self.value = value
+    def __str__(self):
+        return repr(self.value)
+
+
+class URLFragment(object):
+
+    def __init__(self, id_):
+        self.id = id_
+        if id is not None:
+            self.url_fragments = urlparse(id_)
+        else:
+            self.url_fragments = None
+
+    def __str__(self):
+        return repr(self.id + ", " + str(self.url_fragments))
+
+
+def resolveInFile(jsonpath, fileObj):
+    """
+    Run through the `fileObj` json dict for the json path in `fragment` and return the object under the path.
+    """
+    path_expr = jsonpath_rw.parse("$" + ".".join(jsonpath.split("/")))
+    matched_values = [match.value for match in path_expr.find(fileObj)]
+    return matched_values[0] if len(matched_values) > 0 else None
+
+
+def resolveRefFile(json_dump):
+    """
+    Resolves a ref schema file. If the file is in the cache, returns the contents from the cache.
+    """
+    if 'id' in json_dump:
+        _id  = json_dump.get('id')
+        if _id not in cache:
+            cache[_id] = resolve(json_dump)
+        return cache[_id]
+    else:
+        raise IdError("$ref-ed file has no `id`. Will not continue parsing anything. Go fix it!")
+
+
+def parseAsFile(filename):
+    """
+    Opens and resolves a ref schema from file system.
+    """
+    json_dump = json.load(open(filename))
+    return resolveRefFile(json_dump)
+
+
+def parseAsHttp(url):
+    """
+    Use `requests` library to get json located at `url` and call `resolveRefFile` to resolve the $refs in the http-ed json further.
+    """
+    json_dump = None
+    if callable(requests.Response.json):
+        json_dump = requests.get(url).json()
+    else:
+        json_dump = requests.get(url).json
+    return resolveRefFile(json_dump)
+
+
+def parseRef(fragment, value):
+    """
+    Parse the $ref value and resolve using the scheme of resolution from `urlparse(value)`.
+    """
+    ref_frag = urlparse(value)
+    ref_file = ref_frag.netloc + ref_frag.path
+    # ref_frag ->ParseResult(scheme=u'http', netloc=u'localhost:3000', path=u'/ref_schema.json', params='', query='', fragment=u'/definitions/address')
+
+    if ref_frag.scheme in ['http', 'https']:
+        # http/https scheme retrieval of $refs
+        _url = ref_frag.scheme + "://" + ref_file # -> http://localhost:3000/ref_schema.json
+        http_file_json  = parseAsHttp(_url)
+        return resolveInFile(ref_frag.fragment, http_file_json)
+    elif ref_frag.scheme == 'file':
+        # local file absolute and relative paths retrieval of $refs
+        if isfile(ref_file):
+            return resolveInFile(ref_frag.fragment,parseAsFile(ref_file))
+        else:
+            raise Exception("FileNotFoundException:: "+ ref_file)
+    elif ref_frag.scheme == "":
+    # same file internal $ref
+        return resolveInFile(ref_frag.fragment, json.load(open(fragment.url_fragments.path)))
+    else:
+        raise Exception("Scheme of resolution: " + fragment.url_fragments.scheme + " is currently not supported")
+
+
+def resolveInnerElement(fragment, elem):
+    """
+    Resolves inner elements of value attributes. Handles nesting gracefully with standard recursive procedures.
+    """
+    if isinstance(elem, dict):
+        return parse(fragment, elem)
+    elif isinstance(elem, list):
+        return map(lambda x: resolveInnerElement(fragment, x), elem)
+    else:
+        return elem
+
+
+def update(fragment, key, value):
+    """
+    Either resolves the value part if the key is `$ref` or just resolves the inner element in value recursively.
+    """
+    if "$ref" == key:
+        parsedResult = parseRef(fragment, value)
+        return parsedResult
+    else:
+        return {key: resolveInnerElement(fragment, value)}
+
+
+def parse(fragment, json_dict):
+    """
+    Looks at every key-value pair in `json_dict`, resolves $refs and returns new dictionary
+    containing resolutions.
+    This method is not purely functional. It creates a mutable dictionary and puts things into it. Yuck!
+    """
+    mut_dict = {}
+    for (key,value) in json_dict.iteritems():
+        mut_dict.update(update(fragment, key, value))
+    return mut_dict
+
+
+def resolve(json_obj):
+    """
+    Resolves $ref in the `json_obj` and returns a `dict` that has inlined $ref elements.
+    Raises an `IdError` if the `id` key is not present in the `json_obj`.
+    """
+    if 'id' not in json_obj:
+        raise IdError("No `id` field in passed parameter")
+    else:
+        return parse(URLFragment(json_obj.get("id")), json_obj)
+
+
+if __name__ == "__main__":
+    self_ref_json = json.load(open('self_ref_test.schema.json'))
+    #ejson = json.load(open('test_schema.json'))
+    print resolve(self_ref_json)