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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.
60 lines
2.9 KiB
Markdown
60 lines
2.9 KiB
Markdown
---
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title: "S23. Handle custom HTTP methods"
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order: 42
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status: "draft"
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---
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The server rejects HTTP methods it does not know with `400 Bad Request`. To accept an extension method, such as the WebDAV methods of RFC 4918 (`PROPFIND`, `PROPPATCH`, `MKCOL` and friends) or UPnP's `SUBSCRIBE`, register a handler with `CustomRoute()`. Registering the handler is what makes the server accept the method.
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## Basic usage
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```cpp
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svr.CustomRoute("PROPFIND", "/dav/:id",
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[](const httplib::Request &req, httplib::Response &res) {
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// The request body is available as usual
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auto id = req.path_params.at("id");
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res.status = httplib::StatusCode::MultiStatus_207;
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res.set_content(build_multistatus(req.body), "application/xml");
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});
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```
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Patterns work the same way as they do for `Get()`. Regular expressions and path parameters are both available.
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## Advertise your methods with OPTIONS
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A WebDAV client asks the server about its capabilities with `OPTIONS` before doing anything else. cpp-httplib generates neither the `DAV:` header nor `Allow`, so return them yourself. Forget this and clients will turn you away even though your `PROPFIND` works.
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```cpp
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svr.Options("/dav/.*", [](const httplib::Request &req, httplib::Response &res) {
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res.set_header("DAV", "1");
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res.set_header("Allow", "OPTIONS, GET, HEAD, PROPFIND, PROPPATCH, MKCOL");
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});
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```
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## Read the body as a stream
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There is a content reader overload, just like the one on `Post()`. Use it when you would rather not hold a large XML document in memory all at once.
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```cpp
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svr.CustomRoute("REPORT", "/dav/.*",
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[](const httplib::Request &req, httplib::Response &res,
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const httplib::ContentReader &content_reader) {
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content_reader([&](const char *data, size_t data_length) {
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// Process it a chunk at a time
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return true;
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});
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res.status = httplib::StatusCode::MultiStatus_207;
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});
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```
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## Things to keep in mind
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- The method name has to be a valid HTTP method token (RFC 9110), and it must be registered before you call `listen()`
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- `GET`, `HEAD`, `POST`, `PUT`, `DELETE`, `CONNECT`, `OPTIONS`, `TRACE`, `PATCH` and `PRI` cannot be registered here. Use the dedicated methods for those
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- A rejected registration makes `is_valid()` return `false` and `listen()` fail, so the server never starts holding a handler that would never run
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- Static file serving and WebSocket upgrades stay `GET`/`HEAD` only
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> **Note:** cpp-httplib takes you as far as routing the method. If you want to call it WebDAV, generating the `207 Multi-Status` XML, interpreting the `Depth` header and managing locks are all yours to implement. The protocol itself lives outside the library.
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> For the basics of registering handlers, see [S01. Register GET / POST / PUT / DELETE handlers](../s01-handlers).
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