Add Cookbook S01-S22 (draft)

docs-src/pages/en/cookbook/s08-compress-response.md

@@ -0,0 +1,53 @@
+---
+title: "S08. Return a Compressed Response"
+order: 27
+status: "draft"
+---
+
+cpp-httplib automatically compresses response bodies when the client indicates support via `Accept-Encoding`. The handler doesn't need to do anything special. Supported encodings are gzip, Brotli, and Zstd.
+
+## Build-time setup
+
+To enable compression, define the relevant macros before including `httplib.h`:
+
+```cpp
+#define CPPHTTPLIB_ZLIB_SUPPORT     // gzip
+#define CPPHTTPLIB_BROTLI_SUPPORT   // brotli
+#define CPPHTTPLIB_ZSTD_SUPPORT     // zstd
+#include <httplib.h>
+```
+
+You'll also need to link `zlib`, `brotli`, and `zstd` respectively. Enable only what you need.
+
+## Usage
+
+```cpp
+svr.Get("/api/data", [](const httplib::Request &req, httplib::Response &res) {
+  std::string body = build_large_response();
+  res.set_content(body, "application/json");
+});
+```
+
+That's it. If the client sent `Accept-Encoding: gzip`, cpp-httplib compresses the response with gzip automatically. `Content-Encoding: gzip` and `Vary: Accept-Encoding` are added for you.
+
+## Encoding priority
+
+When the client accepts multiple encodings, cpp-httplib picks in this order (among those enabled at build time): Brotli → Zstd → gzip. Your code doesn't need to care — you always get the most efficient option available.
+
+## Streaming responses are compressed too
+
+Streaming responses via `set_chunked_content_provider()` get the same automatic compression.
+
+```cpp
+svr.Get("/events", [](const httplib::Request &req, httplib::Response &res) {
+  res.set_chunked_content_provider(
+    "text/plain",
+    [](size_t offset, httplib::DataSink &sink) {
+      // ...
+    });
+});
+```
+
+> **Note:** Tiny responses barely benefit from compression and just waste CPU time. cpp-httplib skips compression for bodies that are too small to bother with.
+
+> For the client-side counterpart, see C15. Enable Compression.