fix validation spec parsing for docs

Author: pawl

sphinx_json_schema_spec/__init__.py

@@ -0,0 +1,122 @@
+from datetime import datetime
+from docutils import nodes
+import errno
+import os
+
+try:
+    import urllib2 as urllib
+except ImportError:
+    import urllib.request as urllib
+
+from lxml import html
+
+
+VALIDATION_SPEC = "http://json-schema.org/latest/json-schema-validation.html"
+
+
+def setup(app):
+    """
+    Install the plugin.
+
+    :argument sphinx.application.Sphinx app: the Sphinx application context
+
+    """
+
+    app.add_config_value("cache_path", "_cache", "")
+
+    try:
+        os.makedirs(app.config.cache_path)
+    except OSError as error:
+        if error.errno != errno.EEXIST:
+            raise
+
+    path = os.path.join(app.config.cache_path, "spec.html")
+    spec = fetch_or_load(path)
+    app.add_role("validator", docutils_sucks(spec))
+
+
+def fetch_or_load(spec_path):
+    """
+    Fetch a new specification or use the cache if it's current.
+
+    :argument cache_path: the path to a cached specification
+
+    """
+
+    headers = {}
+
+    try:
+        modified = datetime.utcfromtimestamp(os.path.getmtime(spec_path))
+        date = modified.strftime("%a, %d %b %Y %I:%M:%S UTC")
+        headers["If-Modified-Since"] = date
+    except OSError as error:
+        if error.errno != errno.ENOENT:
+            raise
+
+    request = urllib.Request(VALIDATION_SPEC, headers=headers)
+    response = urllib.urlopen(request)
+
+    if response.code == 200:
+        with open(spec_path, "w+b") as spec:
+            spec.writelines(response)
+            spec.seek(0)
+            return html.parse(spec)
+
+    with open(spec_path) as spec:
+        return html.parse(spec)
+
+
+def docutils_sucks(spec):
+    """
+    Yeah.
+
+    It doesn't allow using a class because it does stupid stuff like try to set
+    attributes on the callable object rather than just keeping a dict.
+
+    """
+
+    base_url = VALIDATION_SPEC
+    ref_url = "http://json-schema.org/latest/json-schema-core.html#anchor25"
+    schema_url = "http://json-schema.org/latest/json-schema-core.html#anchor22"
+
+    def validator(name, raw_text, text, lineno, inliner):
+        """
+        Link to the JSON Schema documentation for a validator.
+
+        :argument str name: the name of the role in the document
+        :argument str raw_source: the raw text (role with argument)
+        :argument str text: the argument given to the role
+        :argument int lineno: the line number
+        :argument docutils.parsers.rst.states.Inliner inliner: the inliner
+
+        :returns: 2-tuple of nodes to insert into the document and an iterable
+            of system messages, both possibly empty
+
+        """
+
+        if text == "$ref":
+            return [nodes.reference(raw_text, text, refuri=ref_url)], []
+        elif text == "$schema":
+            return [nodes.reference(raw_text, text, refuri=schema_url)], []
+
+        # find the header in the validation spec containing matching text
+        header = spec.xpath("//h1[contains(text(), '{0}')]".format(text))
+
+        if len(header) == 0:
+            inliner.reporter.warning(
+                "Didn't find a target for {0}".format(text),
+            )
+            uri = base_url
+        else:
+            if len(header) > 1:
+                inliner.reporter.info(
+                    "Found multiple targets for {0}".format(text),
+                )
+
+            # get the href from link in the header
+            uri = base_url + header[0].find('a').attrib["href"]
+
+        reference = nodes.reference(raw_text, text, refuri=uri)
+        return [reference], []
+
+    return validator