feat: add HTTP response compression middleware

.github/actions/build-linux-packages/action.yml

@@ -32,7 +32,7 @@ runs:
           bash -euc '
             export DEBIAN_FRONTEND=noninteractive
             apt-get update
-            apt-get install -y --no-install-recommends build-essential libcjson-dev
+            apt-get install -y --no-install-recommends build-essential libcjson-dev zlib1g-dev
             make clean
             make libchttpx.so
             cp libchttpx.so dist/deb/libchttpx.so
@@ -47,7 +47,7 @@ runs:
           -w /work \
           fedora:42 \
           bash -euc '
-            dnf install -y gcc make cjson-devel
+            dnf install -y gcc make cjson-devel zlib-devel
             make clean
             make libchttpx.so
             cp libchttpx.so dist/rpm/libchttpx.so
@@ -62,7 +62,7 @@ runs:
           -w /work \
           archlinux:base-devel \
           bash -euc '
-            pacman -Sy --noconfirm cjson
+            pacman -Sy --noconfirm cjson zlib
             make clean
             make libchttpx.so
             cp libchttpx.so dist/archlinux/libchttpx.so
@@ -77,7 +77,7 @@ runs:
           -w /work \
           alpine:3.22 \
           sh -euc '
-            apk add --no-cache build-base cjson-dev
+            apk add --no-cache build-base cjson-dev zlib-dev
             make clean
             make libchttpx.so
             cp libchttpx.so dist/apk/libchttpx.so
@@ -109,6 +109,7 @@ runs:
                 "Description: A compact cross-platform HTTP/1.1 server library for C/C++.",
                 f"Version: {version}",
                 "Libs: -L${libdir} -lchttpx",
+                "Libs.private: -lz",
                 "Cflags: -I${includedir}/libchttpx",
                 "",
             ])

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt update
-          sudo apt install -y gcc make libcjson-dev clang-format
+          sudo apt install -y gcc make libcjson-dev zlib1g-dev clang-format
 
       - name: Build binary
         run: make lin
@@ -47,7 +47,7 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt update
-          sudo apt install -y gcc make libcjson-dev libssl-dev openssl
+          sudo apt install -y gcc make libcjson-dev zlib1g-dev libssl-dev openssl
 
       - name: Build TLS-enabled shared library
         run: make TLS=1 libchttpx.so
@@ -58,6 +58,35 @@ jobs:
       - name: Run HTTPS integration test
         run: make test-tls
 
+  build-linux-compression:
+    name: Response compression integration (Linux, zlib)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt update
+          sudo apt install -y gcc make libcjson-dev zlib1g-dev libssl-dev
+
+      - name: Build shared library
+        run: make libchttpx.so
+
+      - name: Build compression example
+        run: make examples-compression
+
+      - name: Run compression integration tests
+        run: make test-compression
+
+      - name: Run compression benchmark
+        run: make benchmark-compression
+
+      - name: Verify TLS build keeps compression support
+        run: |
+          make clean
+          make TLS=1 libchttpx.so
+
   build-windows:
     name: Build (Windows)
     runs-on: windows-latest
@@ -76,6 +105,7 @@ jobs:
           install: >-
             mingw-w64-x86_64-gcc
             mingw-w64-x86_64-make
+            mingw-w64-x86_64-zlib
 
       - name: Build
         run: mingw32-make win SHELL=cmd

.github/workflows/codeql.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Install dependencies
         run: |
           sudo apt update
-          sudo apt install -y gcc make libcjson-dev
+          sudo apt install -y gcc make libcjson-dev zlib1g-dev
 
       - name: Build
         run: make libchttpx.so

Dockerfile

@@ -4,6 +4,7 @@ RUN apt-get update \
     && apt-get install -y --no-install-recommends \
         build-essential \
         libcjson-dev \
+        zlib1g-dev \
     && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /src
@@ -18,6 +19,7 @@ FROM debian:bookworm-slim
 RUN apt-get update \
     && apt-get install -y --no-install-recommends \
         libcjson1 \
+        zlib1g \
     && rm -rf /var/lib/apt/lists/*
 
 COPY --from=builder /pkg/usr/local/lib/libchttpx.so /usr/local/lib/

Makefile

@@ -29,13 +29,15 @@ PKGDIR ?= /pkg/usr/local
 
 WIN_LIB_DIR = tools
 
-LIN_LDFLAGS = -lcjson $(TLS_LDFLAGS)
-WIN_LDFLAGS = -lws2_32 $(TLS_LDFLAGS)
+LIN_LDFLAGS = -lcjson -lz $(TLS_LDFLAGS)
+WIN_LDFLAGS = -lws2_32 -lz $(TLS_LDFLAGS)
 TEST_TARGET = $(BINDIR)/test_core
 TEST_SERVER_TARGET = $(BINDIR)/test_server
 TEST_SANITIZE_TARGET = $(BINDIR)/test_core_sanitize
 TEST_SERVER_SANITIZE_TARGET = $(BINDIR)/test_server_sanitize
 TEST_TLS_TARGET = $(BINDIR)/test_tls
+TEST_COMPRESSION_TARGET = $(BINDIR)/test_compression
+COMPRESSION_BENCHMARK_TARGET = $(BINDIR)/benchmark-compression
 EXAMPLE_SRC = example/basic.c
 EXAMPLE_OBJ = $(OBJDIR)/example/basic.o
 
@@ -73,6 +75,8 @@ $(BINDIR)/example-%: example/%.c $(LIN_SRCS)
 examples-tls:
 	@$(MAKE) TLS=1 $(BINDIR)/example-tls
 
+examples-compression: $(BINDIR)/example-compression
+
 # WINdows build
 # -
 
@@ -108,12 +112,13 @@ lib-install: libchttpx.so
 win-lib:
 	@echo "Building Windows DLL..."
 	if not exist $(BINDIR) mkdir $(BINDIR)
-	$(CC) $(CFLAGS) -std=c11 -D_WIN32 -shared -o $(BINDIR)/$(TARGET_DLL) $(WIN_SRCS) -Wl,--out-implib,$(BINDIR)/libchttpx.a -lws2_32
+	$(CC) $(CFLAGS) -std=c11 -D_WIN32 -shared -o $(BINDIR)/$(TARGET_DLL) $(WIN_SRCS) -Wl,--out-implib,$(BINDIR)/libchttpx.a $(WIN_LDFLAGS)
 
 	@echo "Copying files to $(WIN_LIB_DIR)..."
 	if not exist $(WIN_LIB_DIR) mkdir $(WIN_LIB_DIR)
 	copy /Y $(BINDIR)\$(TARGET_DLL) $(WIN_LIB_DIR)\$(TARGET_DLL)
 	copy /Y $(BINDIR)\libchttpx.a $(WIN_LIB_DIR)\libchttpx.a
+	for /f "delims=" %%i in ('where zlib1.dll 2^>nul') do copy /Y "%%i" $(WIN_LIB_DIR)\zlib1.dll
 	if not exist $(WIN_LIB_DIR)\include mkdir $(WIN_LIB_DIR)\include
 	xcopy /E /I /Y include $(WIN_LIB_DIR)\include
 
@@ -160,6 +165,20 @@ $(TEST_TLS_TARGET): tests/test_tls.c $(LIN_SRCS)
 	@mkdir -p $(BINDIR)
 	$(CC) $(CFLAGS) -std=gnu11 -g tests/test_tls.c $(LIN_SRCS) -o $@ $(LIN_LDFLAGS) -pthread
 
+test-compression: $(TEST_COMPRESSION_TARGET)
+	$(TEST_COMPRESSION_TARGET)
+
+$(TEST_COMPRESSION_TARGET): tests/test_compression.c $(LIN_SRCS)
+	@mkdir -p $(BINDIR)
+	$(CC) $(CFLAGS) -std=gnu11 -g tests/test_compression.c $(LIN_SRCS) -o $@ $(LIN_LDFLAGS) -pthread
+
+benchmark-compression: $(COMPRESSION_BENCHMARK_TARGET)
+	$(COMPRESSION_BENCHMARK_TARGET)
+
+$(COMPRESSION_BENCHMARK_TARGET): benchmarks/compression.c $(LIN_SRCS)
+	@mkdir -p $(BINDIR)
+	$(CC) $(CFLAGS) -std=gnu11 -O2 benchmarks/compression.c $(LIN_SRCS) -o $@ $(LIN_LDFLAGS) -pthread
+
 # LINux lib compile
 # -
 

README.md

@@ -17,6 +17,7 @@ The library is designed so handlers contain application logic instead of repetit
 - multipart forms, multiple uploads, upload policies, and temporary-file cleanup
 - request IDs and `Accept-Language` negotiation
 - CORS, cookies, logging callbacks, and rate limiting
+- optional gzip response compression with `Accept-Encoding` negotiation
 - configurable server limits and graceful shutdown
 
 > `cHTTPX_ResFile()` currently reads the complete file into memory. Streaming responses, `sendfile()`, and zero-copy output are not implemented in the current API.
@@ -124,11 +125,11 @@ CMD ["/usr/local/bin/my-server"]
 
 ### Build from source on Linux
 
-Requirements: GCC, Make, pkg-config, and cJSON development files.
+Requirements: GCC, Make, pkg-config, cJSON development files, and zlib development files.
 
 ```bash
 sudo apt update
-sudo apt install -y build-essential pkg-config libcjson-dev
+sudo apt install -y build-essential pkg-config libcjson-dev zlib1g-dev
 
 git clone https://github.com/netcorelink/libchttpx.git
 cd libchttpx
@@ -154,9 +155,18 @@ make test-tls
 
 See [Native TLS / HTTPS](docs/tls/README.md) for server certificates, HTTPS remote calls, custom CA verification, and mTLS.
 
+Response compression is included in the standard build. zlib is a normal libchttpx dependency; applications enable compression at runtime with `cHTTPX_CompressionUse()` and configure minimum size, level, MIME policy, or custom providers in code.
+
+```bash
+make test-compression
+make benchmark-compression
+```
+
+TLS remains independently optional: `make TLS=1 libchttpx.so`. See [Response compression](docs/compression/README.md).
+
 ### Build from source on Windows
 
-Use MinGW/GCC. The Windows build uses the bundled `lib/cjson` source.
+Use MinGW/GCC. The Windows build uses the bundled `lib/cjson` source and requires zlib (for MSYS2/MinGW64: `mingw-w64-x86_64-zlib`).
 
 ```powershell
 git clone https://github.com/netcorelink/libchttpx.git
@@ -176,6 +186,7 @@ Detailed documentation is split by functionality:
 - [App runtime, multiple servers, AppRemote, Call and CallEx](docs/app/README.md)
 - [Server configuration, limits, lifecycle and error codes](docs/server/README.md)
 - [Native TLS / HTTPS](docs/tls/README.md)
+- [Response compression](docs/compression/README.md)
 - [Routing and route groups](docs/routing/README.md)
 - [Middleware](docs/middleware/README.md)
 - [Requests, headers, params, queries and body access](docs/request/README.md)

README_RU.md

@@ -17,6 +17,7 @@
 - multipart forms, несколько файлов, upload policy и автоматическое удаление временных файлов
 - request ID и `Accept-Language` negotiation
 - CORS, cookies, callback-based logging и rate limiting
+- optional gzip-сжатие ответов с `Accept-Encoding` negotiation
 - лимиты сервера и graceful shutdown
 
 > `cHTTPX_ResFile()` пока полностью читает файл в память. Streaming response, `sendfile()` и zero-copy output в текущем API не реализованы.
@@ -124,7 +125,7 @@ CMD ["/usr/local/bin/my-server"]
 
 ```bash
 sudo apt update
-sudo apt install -y build-essential pkg-config libcjson-dev
+sudo apt install -y build-essential pkg-config libcjson-dev zlib1g-dev
 
 git clone https://github.com/netcorelink/libchttpx.git
 cd libchttpx
@@ -150,9 +151,18 @@ make test-tls
 
 Настройка server certificate, HTTPS remote calls, custom CA и mTLS описана в [Native TLS / HTTPS](docs/tls/README_RU.md).
 
+Сжатие ответов входит в обычную сборку libchttpx. zlib — стандартная зависимость библиотеки, а включение gzip выполняется уже в коде приложения через `cHTTPX_CompressionUse()`. Размер, level, MIME policy и providers тоже задаются через config.
+
+```bash
+make test-compression
+make benchmark-compression
+```
+
+TLS остаётся отдельной опцией сборки: `make TLS=1 libchttpx.so`. Подробнее: [Сжатие HTTP-ответов](docs/compression/README_RU.md).
+
 ### Самостоятельная сборка на Windows
 
-Используется MinGW/GCC. Для Windows cJSON уже находится в `lib/cjson`.
+Используется MinGW/GCC. Для Windows cJSON уже находится в `lib/cjson`, а zlib должен быть установлен (для MSYS2/MinGW64: `mingw-w64-x86_64-zlib`).
 
 ```powershell
 git clone https://github.com/netcorelink/libchttpx.git
@@ -172,6 +182,7 @@ DLL, import library и headers копируются в `tools/`.
 - [App runtime, несколько серверов, AppRemote, Call и CallEx](docs/app/README_RU.md)
 - [Конфигурация сервера, лимиты, lifecycle и error codes](docs/server/README_RU.md)
 - [Native TLS / HTTPS](docs/tls/README_RU.md)
+- [Сжатие HTTP-ответов](docs/compression/README_RU.md)
 - [Routing и route groups](docs/routing/README_RU.md)
 - [Middleware](docs/middleware/README_RU.md)
 - [Requests, headers, params, queries и body](docs/request/README_RU.md)

benchmarks/compression.c

@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include <zlib.h>
+
+#define PAYLOAD_SIZE (1024 * 1024)
+#define ITERATIONS 100
+
+static double elapsed_seconds(struct timespec start, struct timespec end)
+{
+    return (double)(end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) / 1000000000.0;
+}
+
+static void build_payload(unsigned char* payload, size_t size)
+{
+    static const char row[] =
+        "{\"id\":12345,\"username\":\"artem\",\"active\":true,"
+        "\"message\":\"response compression benchmark payload\"}\n";
+
+    size_t offset = 0;
+    while (offset < size)
+    {
+        size_t remaining = size - offset;
+        size_t chunk = sizeof(row) - 1;
+        if (chunk > remaining)
+            chunk = remaining;
+        memcpy(payload + offset, row, chunk);
+        offset += chunk;
+    }
+}
+
+static int gzip_once(const unsigned char* input, size_t input_size, int level, unsigned char* output, size_t output_capacity, size_t* output_size)
+{
+    z_stream stream;
+    memset(&stream, 0, sizeof(stream));
+
+    if (deflateInit2(&stream, level, Z_DEFLATED, 15 + 16, 8, Z_DEFAULT_STRATEGY) != Z_OK)
+        return 0;
+
+    stream.next_in = (Bytef*)input;
+    stream.avail_in = (uInt)input_size;
+    stream.next_out = output;
+    stream.avail_out = (uInt)output_capacity;
+
+    int result = deflate(&stream, Z_FINISH);
+    if (result != Z_STREAM_END)
+    {
+        deflateEnd(&stream);
+        return 0;
+    }
+
+    *output_size = output_capacity - stream.avail_out;
+    deflateEnd(&stream);
+    return 1;
+}
+
+int main(void)
+{
+    unsigned char* payload = malloc(PAYLOAD_SIZE);
+    if (!payload)
+        return 1;
+    build_payload(payload, PAYLOAD_SIZE);
+
+    uLong bound = compressBound(PAYLOAD_SIZE) + 64;
+    unsigned char* compressed = malloc((size_t)bound);
+    if (!compressed)
+    {
+        free(payload);
+        return 1;
+    }
+
+    const int levels[] = {1, 5, 9};
+    puts("level,input_bytes,compressed_bytes,ratio,throughput_mib_s");
+
+    for (size_t level_index = 0; level_index < sizeof(levels) / sizeof(levels[0]); level_index++)
+    {
+        int level = levels[level_index];
+        size_t compressed_size = 0;
+
+        struct timespec start;
+        struct timespec end;
+        clock_gettime(CLOCK_MONOTONIC, &start);
+
+        for (int iteration = 0; iteration < ITERATIONS; iteration++)
+        {
+            if (!gzip_once(payload, PAYLOAD_SIZE, level, compressed, (size_t)bound, &compressed_size))
+            {
+                free(compressed);
+                free(payload);
+                return 1;
+            }
+        }
+
+        clock_gettime(CLOCK_MONOTONIC, &end);
+        double seconds = elapsed_seconds(start, end);
+        double mib = ((double)PAYLOAD_SIZE * ITERATIONS) / (1024.0 * 1024.0);
+        double ratio = (double)compressed_size / (double)PAYLOAD_SIZE;
+
+        printf("%d,%d,%zu,%.4f,%.2f\n", level, PAYLOAD_SIZE, compressed_size, ratio, mib / seconds);
+    }
+
+    free(compressed);
+    free(payload);
+    return 0;
+}