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#include "server/proxy.h"
#include <event2/buffer.h>
#include <event2/http.h>
#include <event2/http_compat.h>
#include <event2/keyvalq_struct.h>
#include <glog/logging.h>
#include <algorithm>
#include <string>
#include <unordered_set>
#include <vector>
#include "monitoring/monitoring.h"
#include "proto/ct.pb.h"
#include "server/json_output.h"
#include "util/libevent_wrapper.h"
using ct::ClusterNodeState;
using std::bind;
using std::getline;
using std::make_pair;
using std::pair;
using std::placeholders::_1;
using std::rand;
using std::string;
using std::stringstream;
using std::unique_ptr;
using std::unordered_set;
using std::vector;
using util::Executor;
using util::Task;
namespace cert_trans {
namespace {
static Counter<string>* total_proxied_requests(
Counter<string>::New("total_proxied_requests", "path",
"Number of proxied API requests by path."));
static Counter<string, int>* total_proxied_responses(
Counter<string, int>::New("total_proxied_responses", "path", "status_code",
"Number of proxied API requests by path "
"and status code."));
void ProxyRequestDone(libevent::Base* base, evhttp_request* request,
const string& path, UrlFetcher::Response* response,
Task* task) {
CHECK_NOTNULL(request);
CHECK_NOTNULL(task);
unique_ptr<UrlFetcher::Response> response_deleter(CHECK_NOTNULL(response));
total_proxied_requests->Increment(path);
total_proxied_responses->Increment(path, response->status_code);
if (!task->status().ok()) {
return SendJsonError(base, request, HTTP_INTERNAL,
"Proxied request failed.");
}
// TODO(alcutter): Consider retrying the proxied request some number of times
// in the case where the request fails.
FilterHeaders(&response->headers);
for (auto it(response->headers.begin()); it != response->headers.end();
++it) {
CHECK_EQ(evhttp_add_header(evhttp_request_get_output_headers(request),
it->first.c_str(), it->second.c_str()),
0);
}
CHECK_GT(evbuffer_add_printf(evhttp_request_get_output_buffer(request), "%s",
response->body.c_str()),
-1);
const int response_code(response->status_code);
base->Add([request, response_code]() {
evhttp_send_reply(request, response_code, /*reason*/ NULL,
/*databuf*/ NULL);
});
}
} // namespace
// Filters out any headers which should not be proxied on.
// See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.10
void FilterHeaders(UrlFetcher::Headers* headers) {
const auto connection_range(headers->equal_range("Connection"));
unordered_set<string> connection_headers;
for (auto it(connection_range.first); it != connection_range.second; ++it) {
stringstream ss(it->second);
string token;
while (getline(ss, token, ',')) {
token.erase(remove(token.begin(), token.end(), ' '), token.end());
if (!token.empty()) {
connection_headers.insert(token);
}
}
}
headers->erase(connection_range.first, connection_range.second);
for (const string& header : connection_headers) {
const auto range(headers->equal_range(header));
if (range.first != headers->end()) {
headers->erase(range.first, range.second);
}
}
}
Proxy::Proxy(libevent::Base* base,
const GetFreshNodesFunction& get_fresh_nodes, UrlFetcher* fetcher,
Executor* executor)
: base_(CHECK_NOTNULL(base)),
get_fresh_nodes_(get_fresh_nodes),
fetcher_(CHECK_NOTNULL(fetcher)),
executor_(CHECK_NOTNULL(executor)) {
CHECK(get_fresh_nodes_);
}
void Proxy::ProxyRequest(evhttp_request* req) const {
CHECK_NOTNULL(req);
const vector<ClusterNodeState> fresh_nodes(get_fresh_nodes_());
if (fresh_nodes.empty()) {
return SendJsonError(base_, req, HTTP_SERVUNAVAIL,
"No node able to serve request.");
}
const ClusterNodeState& target(fresh_nodes[rand() % fresh_nodes.size()]);
URL url(evhttp_request_uri(req));
url.SetProtocol("http");
url.SetHost(target.hostname());
url.SetPort(target.log_port());
UrlFetcher::Request fetcher_req(url);
switch (evhttp_request_get_command(req)) {
case EVHTTP_REQ_DELETE:
fetcher_req.verb = UrlFetcher::Verb::DELETE;
break;
case EVHTTP_REQ_GET:
fetcher_req.verb = UrlFetcher::Verb::GET;
break;
case EVHTTP_REQ_POST:
fetcher_req.verb = UrlFetcher::Verb::POST;
break;
case EVHTTP_REQ_PUT:
fetcher_req.verb = UrlFetcher::Verb::PUT;
break;
default:
return SendJsonError(base_, req, HTTP_BADMETHOD,
"Bad method requested.");
break;
}
for (evkeyval* ptr = evhttp_request_get_input_headers(req)->tqh_first; ptr;
ptr = ptr->next.tqe_next) {
fetcher_req.headers.insert(make_pair(ptr->key, ptr->value));
}
FilterHeaders(&fetcher_req.headers);
if (fetcher_req.verb == UrlFetcher::Verb::PUT ||
fetcher_req.verb == UrlFetcher::Verb::POST) {
const size_t body_length(
evbuffer_get_length(evhttp_request_get_input_buffer(req)));
string body(reinterpret_cast<const char*>(evbuffer_pullup(
evhttp_request_get_input_buffer(req), body_length)),
body_length);
CHECK_EQ(0, evbuffer_drain(evhttp_request_get_input_buffer(req),
body_length));
fetcher_req.body.swap(body);
}
VLOG(1) << "Proxying request to " << url.Host() << ":" << url.Port()
<< url.PathQuery();
UrlFetcher::Response* resp(new UrlFetcher::Response);
fetcher_->Fetch(fetcher_req, resp, new Task(bind(&ProxyRequestDone, base_,
req, url.Path(), resp, _1),
executor_));
}
} // namespace cert_trans
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