Generate swagger-ui output for client-server API

Depends on:
https://github.com/matrix-org/matrix-doc/pull/212
https://github.com/matrix-org/matrix-doc/pull/208
https://github.com/matrix-org/matrix-doc/pull/207
for the actual rendered output to not throw javascript errors at runtime.

scripts/dump-swagger.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python2
+
+# dump-swagger reads all of the swagger API docs used in spec generation and
+# outputs a JSON file which merges them all, for use as input to a swagger UI
+# viewer.
+# See https://github.com/swagger-api/swagger-ui for details of swagger-ui.
+
+import errno
+import json
+import os.path
+import re
+import shutil
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "templating"))
+from matrix_templates.units import resolve_references, MatrixUnits
+
+if len(sys.argv) < 2 or len(sys.argv) > 3:
+    sys.stderr.write("usage: %s output_directory [client_release_label]\n" % (sys.argv[0],))
+    sys.exit(1)
+
+output_directory = sys.argv[1]
+release_label = sys.argv[2] if len(sys.argv) > 2 else "unstable"
+
+major_version = release_label
+match = re.match("^(r\d)+(\.\d+)?$", major_version)
+if match:
+    major_version = match.group(1)
+
+apis = MatrixUnits().load_swagger_apis()
+
+output = {
+    "basePath": "/matrix/client/" + major_version,
+    "consumes": ["application/json"],
+    "produces": ["application/json"],
+    "host": "localhost:8008",
+    "info": {
+        "title": "Matrix Client-Server API",
+        "version": release_label,
+    },
+    "paths": {},
+    "swagger": "2.0",
+}
+
+for file, contents in apis.items():
+    for path, methods in contents["paths"].items():
+        for method, spec in methods.items():
+            if "tags" in spec.keys():
+                if path not in output["paths"]:
+                    output["paths"][path] = {}
+                output["paths"][path][method] = spec
+
+path = os.path.join(output_directory, "api-docs")
+try:
+    os.makedirs(os.path.dirname(path))
+except OSError as e:
+    if e.errno != errno.EEXIST:
+        raise
+
+with open(path, "w") as f:
+    text = json.dumps(output, sort_keys=True, indent=4)
+    text = text.replace("%CLIENT_RELEASE_LABEL%", release_label)
+    text = text.replace("%CLIENT_MAJOR_VERSION%", major_version)
+    f.write(text)