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* Add Server::CustomRoute() for HTTP methods outside the built-in set parse_request_line validates the request method against a fixed whitelist and rejects anything else with 400 before routing runs. That blocks WebDAV, where PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK and UNLOCK are ordinary methods defined by RFC 4918, and it blocks extension methods such as UPnP's SUBSCRIBE. The need has been open since #847. Registering a handler is now what makes the server accept a method: svr.CustomRoute("PROPFIND", "/dav/:id", handler); Because custom methods go through the normal dispatch path, patterns work the way they do for Get() and friends, and the request body is available in req.body. Serving these methods through set_pre_routing_handler was never enough: the body has not been read at that point, so PROPPATCH and LOCK, which require one, could not be implemented at all. A HandlerWithContentReader overload is available too. The content reader gate in routing() also fires when a custom method carries no body, matching what expect_content() does unconditionally for POST/PUT/PATCH/DELETE, so a body-less PROPFIND (RFC 4918 treats one as allprop) reaches its handler instead of falling through to 404. Method names are validated as RFC 9110 tokens, and the ten built-in methods are refused. Seven of them are dispatched by the if/else chain in routing() before the custom tables are consulted, so a route registered for one could never fire; CONNECT, TRACE and PRI carry protocol-level meaning this library does not route. A refused registration makes is_valid() return false, so listen() fails rather than starting a server holding a handler that would never run. This is also why SSLServer::is_valid() now chains to Server::is_valid() instead of only checking ctx_. Servers that never call CustomRoute() keep the previous per-request cost: the built-in method set is checked first and short-circuits, and the custom lookup returns early on an empty map. * Add cookbook recipe for custom HTTP methods The CustomRoute() docs were a section inside S01, which pushed that page to 90 lines, the longest in the cookbook, and mixed a separate feature into a page about registering GET/POST/PUT/DELETE handlers. Move the section into its own recipe and give it room for the part that was missing: the OPTIONS handler returning DAV: and Allow, which WebDAV clients probe for before anything else. S01 goes back to 68 lines and keeps a pointer to the new page. The recipe is titled after the API rather than after WebDAV, and says outright that generating the 207 Multi-Status XML, interpreting Depth and managing locks are the reader's job. Routing the method is all the library does. S23 takes order 42, so the TLS, SSE and WebSocket recipes shift to 43-57. That only moves the sort key. Filenames, the T01/E01/W01 labels, the published URLs and every cross-reference are untouched.
85 lines
3.4 KiB
Markdown
85 lines
3.4 KiB
Markdown
---
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title: "E02. SSEでイベント名を使い分ける"
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order: 49
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status: "draft"
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---
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SSEでは、1本のストリームで複数の種類のイベントを送れます。`event:`フィールドで名前を付けると、クライアント側で種類ごとに別々のハンドラを呼べます。チャットの「新規メッセージ」「入室」「退室」のような場面で便利です。
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## イベント名付きで送る
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```cpp
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auto send_event = [](httplib::DataSink &sink,
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const std::string &event,
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const std::string &data) {
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std::string msg = "event: " + event + "\n"
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+ "data: " + data + "\n\n";
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sink.write(msg.data(), msg.size());
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};
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svr.Get("/chat/stream", [&](const httplib::Request &req, httplib::Response &res) {
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res.set_chunked_content_provider(
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"text/event-stream",
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[&, send_event](size_t offset, httplib::DataSink &sink) {
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send_event(sink, "message", "Hello!");
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std::this_thread::sleep_for(std::chrono::seconds(2));
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send_event(sink, "join", "alice");
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std::this_thread::sleep_for(std::chrono::seconds(2));
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send_event(sink, "leave", "bob");
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std::this_thread::sleep_for(std::chrono::seconds(2));
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return true;
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});
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});
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```
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1メッセージは`event:` → `data:` → 空行、の形式です。`event:`を書かないと、クライアント側ではデフォルトの`"message"`イベントとして扱われます。
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## IDを付けて再接続に備える
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`id:`フィールドを一緒に送ると、クライアントが切断→再接続したときに`Last-Event-ID`ヘッダーで「どこまで受け取ったか」を教えてくれます。
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```cpp
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auto send_event = [](httplib::DataSink &sink,
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const std::string &event,
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const std::string &data,
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const std::string &id) {
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std::string msg = "id: " + id + "\n"
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+ "event: " + event + "\n"
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+ "data: " + data + "\n\n";
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sink.write(msg.data(), msg.size());
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};
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send_event(sink, "message", "Hello!", "42");
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```
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IDの付け方は自由です。連番でもUUIDでも、サーバー側で重複せず順序が追えるものを選びましょう。再接続の詳細は[E03. SSEの再接続を処理する](../e03-sse-reconnect)を参照してください。
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## JSONをdataに乗せる
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構造化されたデータを送りたいときは、`data:`の中身をJSONにするのが定番です。
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```cpp
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nlohmann::json payload = {
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{"user", "alice"},
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{"text", "Hello!"},
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};
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send_event(sink, "message", payload.dump(), "42");
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```
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クライアント側では受け取った`data`をそのままJSONパースすれば、元のオブジェクトに戻せます。
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## データに改行が含まれる場合
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`data:`の値に改行が入るときは、各行の先頭に`data: `を付けて複数行に分けて送ります。
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```cpp
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std::string msg = "data: line1\n"
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"data: line2\n"
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"data: line3\n\n";
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sink.write(msg.data(), msg.size());
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```
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クライアント側では、これらが改行でつながった1つの`data`として復元されます。
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> **Note:** `event:`を使うとクライアント側のハンドリングがきれいになりますが、ブラウザのDevToolsで見たときに種類別で識別しやすくなるというメリットもあります。デバッグ時に効いてきます。
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