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#include "Logging.h"
#include "Utils.h"
#include "WebServer.h"
#include <chrono>
#include <iostream>
#include <mutex>
#include <set>
#include <sstream>
#include <unordered_map>
using ::Logging::Log;
class Sessions {
public:
struct SessionInfo {
std::chrono::time_point<std::chrono::steady_clock> creation_time;
std::string transcript;
};
// Create a new session and return its identifier.
std::string CreateSession()
{
// Each char in RandomString has 5.9 bits of entropy, so 16 chars gives
// us 94 bits of entropy - unlikely to ever collide or be guessed.
std::string id = RandomString(16);
SessionInfo info;
info.creation_time = std::chrono::steady_clock::now();
std::scoped_lock l(mu_);
sessions_[id] = info;
return id;
}
// Look up a session by ID. The session info is copied into `info`.
bool GetSession(const std::string& id, SessionInfo& info)
{
std::scoped_lock l(mu_);
auto session_iter = sessions_.find(id);
if (session_iter == sessions_.end()) {
return false;
}
info = session_iter->second;
return true;
}
void SetSession(const std::string& id, SessionInfo&& info)
{
std::scoped_lock l(mu_);
sessions_[id] = std::move(info);
}
void PruneSessions(std::chrono::duration<double> max_age)
{
auto now = std::chrono::steady_clock::now();
std::set<std::string> pruned_sessions;
{
std::scoped_lock l(mu_);
auto session_iter = sessions_.begin();
while (session_iter != sessions_.end()) {
std::chrono::duration<double> age = now - session_iter->second.creation_time;
if (age > max_age) {
pruned_sessions.insert(session_iter->first);
sessions_.erase(session_iter++);
} else {
++session_iter;
}
}
}
if (!pruned_sessions.empty()) {
std::ostringstream sessions_oss;
for (auto& session : pruned_sessions) {
sessions_oss << ' ' << session;
}
Log("Pruned sessions{}\n", sessions_oss.str());
}
}
private:
std::mutex mu_;
std::unordered_map<std::string, SessionInfo> sessions_;
};
int main () {
WebServer::WebServer ws(8080);
Sessions s;
// TODO rm
{
Sessions::SessionInfo info;
info.creation_time = std::chrono::steady_clock::now();
s.SetSession("test_session", std::move(info));
}
ws.RegisterDefaultHandler(
[&](int& status_code, std::string& payload,
WebServer::ContentType& type) -> void {
std::string resp = "Hello, world!\n";
status_code = 200;
payload = resp;
type = WebServer::HTML;
});
ws.RegisterPathHandler("GET", "/api/v0/create_session",
[&](int& status_code, std::string& payload,
WebServer::ContentType& type) -> void {
std::string id = s.CreateSession();
// Each char in RandomString has 5.9 bits of entropy, so 16 chars gives
// us 94 bits of entropy - unlikely to ever collide or be guessed.
std::string resp = "{session_id:" + id + "}";
Log("Created session {}\n", id);
status_code = 200;
payload = resp;
type = WebServer::JSON;
});
ws.RegisterPathHandler("POST", "/api/v0/set_transcript",
[&](int& status_code, std::string& payload,
WebServer::ContentType& type) -> void {
// Payload must look like "$session_id $transcript"
size_t space_pos = payload.find(' ');
std::string session_id;
std::string transcript;
if (space_pos == std::string::npos) {
session_id = payload;
} else {
session_id = payload.substr(0, space_pos);
transcript = payload.substr(space_pos + 1);
}
Log("Updating session {}\n", session_id);
Sessions::SessionInfo info;
if (!s.GetSession(session_id, info)) {
status_code = 404;
payload = "Failed to find session " + session_id;
type = WebServer::HTML;
return;
}
info.transcript = transcript;
s.SetSession(session_id, std::move(info));
Log("Updated transcript of session {}: {}\n", session_id, transcript);
status_code = 200;
payload.clear();
type = WebServer::HTML;
});
ws.RegisterPathHandler("GET", "/api/v0/get_transcript",
[&](int& status_code, std::string& payload,
WebServer::ContentType& type) -> void {
// Payload must look like "$session_id $transcript"
std::string session_id = payload;
Sessions::SessionInfo info;
if (!s.GetSession(session_id, info)) {
status_code = 404;
payload = "Failed to find session " + session_id;
type = WebServer::HTML;
return;
}
status_code = 200;
payload = info.transcript;
type = WebServer::HTML;
});
bool run = true;
auto server_thd = std::async(std::launch::async, [&]() -> void {
ws.Run(&run);
});
auto prune_thd = std::async(std::launch::async, [&]() -> void {
while (run) {
std::this_thread::sleep_for(std::chrono::seconds(1));
s.PruneSessions(std::chrono::days(1));
}
});
Log("Started webserver. Press enter to exit.\n");
std::string line;
while (std::getline(std::cin, line)) {
break;
}
run = false;
// Wait for server to exit.
Log("Joining server thread...\n");
server_thd.get();
Log("Done!\n");
return 0;
}
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