iss #24: [tmp] proxied response (in progress...)

examples/example.json

@@ -94,6 +94,33 @@
             "delay": 15, // seconds
             "response": "so long",
             "code": 503
+        },
+
+        //proxy some requests to upstream
+        {
+            "path_regexp": "^/proxy/(.*)",
+            "response_proxy": "http://example.com/path/$1"
+        },
+
+        //proxy request with some delay
+        {
+            "path_regexp": "^/slow_proxy/(.*)/(.*)$",
+            "response_proxy": "http://example.com/otherpath/$1/$2",
+            "delay": 10 //seconds
+        },
+
+        //proxy with some response headers replaced to config defined
+        {
+            "path_regexp": "^/fixed_proxy/(.*)/(.*)$",
+            "response_proxy": "http://example.com/otherpath/$1/$2",
+            "headers": {
+                "Server": "MyServer/0.1"
+            }
+        },
+        {
+            "path_regexp": "^/fixed_proxy2/(.*)$",
+            "response_proxy": "http://example.com/otherpath/$1",
+            "headers_file": "page1.headers"
         }
     ]
 }

zaglushka.py

@@ -6,6 +6,7 @@
 import json
 import httplib
 import time
+from copy import deepcopy
 from os import path
 from collections import namedtuple
 
@@ -14,6 +15,7 @@
 from tornado.options import define, options
 from tornado.httpserver import HTTPServer
 from tornado.httputil import HTTPHeaders
+from tornado.httpclient import AsyncHTTPClient, HTTPRequest
 
 logger = logging.getLogger('zaglushka')
 
@@ -67,14 +69,7 @@ def __init__(self, raw_config, config_full_path):
                 rules.append(Rule(matcher, responder))
             else:
                 logger.warn('Unable to build matcher from url spec #{}, skipping'.format(num))
-        default_response = static_response(
-            body='',
-            headers_func=build_static_headers_func({
-                'X-Zaglushka-Default-Response': 'true',
-            }),
-            code=httplib.NOT_FOUND
-        )
-        rules.append(Rule(always_match, default_response))
+        rules.append(Rule(always_match, default_response()))
         self.rules = rules
         self.stubs_base_path = stubs_base_path
 
@@ -183,6 +178,16 @@ def _body_func(handler, ready_cb):
                         **stub_kwargs)
 
 
+def default_response():
+    return static_response(
+        body='',
+        headers_func=build_static_headers_func({
+            'X-Zaglushka-Default-Response': 'true',
+        }),
+        code=httplib.NOT_FOUND
+    )
+
+
 def filebased_response(full_path, headers_func, warn_func=None, **stub_kwargs):
 
     def _body_func(handler, ready_cb):
@@ -200,6 +205,51 @@ def _body_func(handler, ready_cb):
                         **stub_kwargs)
 
 
+def proxied_response(url_pattern, proxy_url, headers_func, warn_func=None, **stub_kwargs):
+
+    try:
+        url_regexp = re.compile(url_pattern)
+    except re.error as e:
+        if warn_func is not None:
+            warn_func('Unable to compile url pattern "{}": {}'.format(url_pattern, e))
+        return default_response()
+
+    def _body_func(handler, ready_cb):
+        match = url_regexp.search(handler.request.uri)
+        if match is None:
+            handler.set_header('X-Zaglushka-Failed-Response', 'true')
+            return ready_cb()
+        url = proxy_url
+        for i, group in enumerate(match.groups()):
+            url = url.replace('${}'.format(i), group)
+        http_client = handler.application.settings['http_client']
+        request = HTTPRequest(url, method=handler.request.method, headers=handler.request.headers,
+                              body=handler.request.body, follow_redirects=False)
+
+        def _on_proxied_request_ready(response):
+            # TODO: delay ? what about - нужно не сложить а смержить
+            # TODO: 599 response ?
+            if response.code == 599:  # special tornado status code
+                pass
+            headers_before = deepcopy(handler.headers)
+            handler.write(response.body)
+            for header, value in response.headers.iteritems():
+                handler.add_header(header, value)
+            # replace with headers from config if any
+            for header, _ in headers_before.get_all():
+                handler.clear_header(header)
+                for value in headers_before.get_list(header):
+                    handler.add_header(header, value)
+            handler.set_status(response.code)
+            ready_cb()
+
+        http_client.fetch(request, callback=_on_proxied_request_ready)
+
+    return ResponseStub(headers_func=headers_func,
+                        body_func=_body_func,
+                        **stub_kwargs)
+
+
 def choose_headers_func(spec, base_stubs_path):
     paths = set()
     if 'headers' in spec:
@@ -386,10 +436,12 @@ def compute_etag(self):
 
 
 def build_app(zaglushka_config, debug=False):
+    http_client = AsyncHTTPClient()
     return Application(
         handlers=[(r'.*', StubHandler)],
         debug=debug,
-        zaglushka_config=zaglushka_config
+        zaglushka_config=zaglushka_config,
+        http_client=http_client
     )