Use boost.http encoder/decoder services

.github/workflows/ci.yml

@@ -263,8 +263,8 @@ jobs:
           apt-get-add-architecture: ${{ matrix.x86 && 'i386' || '' }}
           apt-get: >-
             ${{ matrix.install }}
-            build-essential libssl-dev zlib1g-dev libbrotli-dev
-            ${{ matrix.x86 && 'libssl-dev:i386 zlib1g-dev:i386 libbrotli-dev:i386' || '' }}
+            build-essential libssl-dev zlib1g-dev libbrotli-dev libzstd-dev
+            ${{ matrix.x86 && 'libssl-dev:i386 zlib1g-dev:i386 libbrotli-dev:i386 libzstd-dev:i386' || '' }}
 
       - name: Clone Boost
         uses: alandefreitas/cpp-actions/boost-clone@v1.9.4
@@ -283,7 +283,7 @@ jobs:
         if: ${{ startsWith(matrix.runs-on, 'windows') }}
         id: package-install-windows
         with:
-          vcpkg: zlib brotli openssl
+          vcpkg: zlib brotli zstd openssl
           vcpkg-dir: vcpkg-root
           vcpkg-triplet: ${{ matrix.x86 && 'x86-windows-static' || 'x64-windows' }}
 
@@ -303,6 +303,7 @@ jobs:
 
           echo "using zlib    : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\" <name>zlib                              : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
           echo "using brotli  : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\"                                         : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
+          echo "using zstd    : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\"                                         : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
           echo "using openssl : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\" <ssl-name>libssl <crypto-name>libcrypto : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
 
           cat user-config.jam

CMakeLists.txt

@@ -193,33 +193,6 @@ if (Libpsl_FOUND)
     target_compile_definitions(boost_burl PRIVATE BOOST_BURL_HAS_LIBPSL)
 endif ()
 
-#-------------------------------------------------
-#
-# Compression backends (optional)
-#
-#-------------------------------------------------
-
-# zlib: deflate and gzip content codings
-find_package(ZLIB)
-if (ZLIB_FOUND)
-    target_link_libraries(boost_burl PRIVATE ZLIB::ZLIB)
-    target_compile_definitions(boost_burl PUBLIC BOOST_BURL_HAS_ZLIB)
-endif ()
-
-# Brotli: br content coding (decoding only)
-find_package(Brotli)
-if (Brotli_FOUND)
-    target_link_libraries(boost_burl PRIVATE Brotli::common Brotli::decoder)
-    target_compile_definitions(boost_burl PUBLIC BOOST_BURL_HAS_BROTLI)
-endif ()
-
-# Zstandard: zstd content coding
-find_package(Zstd)
-if (Zstd_FOUND)
-    target_link_libraries(boost_burl PRIVATE Zstd::Zstd)
-    target_compile_definitions(boost_burl PUBLIC BOOST_BURL_HAS_ZSTD)
-endif ()
-
 #-------------------------------------------------
 #
 # Tests

README.md

@@ -25,8 +25,8 @@ One line to make a request.
 - **Automatic redirects** — 301/302/303/307/308 with standards-compliant
   method changes, `Referer` handling, and credential stripping on
   cross-origin hops.
-- **Content encodings** — transparent `gzip`, `deflate`, and `br` decoding
-  when the corresponding decode service is installed.
+- **Content encodings** — transparent `gzip`, `deflate`, `br`, and `zstd`
+  decoding when the corresponding decode service is installed.
 - **Cookies** — RFC 6265bis jar with optional public-suffix validation (libpsl).
 - **Authentication** — Basic and Bearer, per client or per request.
 - **Proxies** — `http`, `socks5`, with credentials.

build/Jamfile

@@ -11,9 +11,6 @@ import ac ;
 import config : requires ;
 
 using openssl ;
-using zlib ;
-using brotli ;
-using zstd ;
 
 constant c11-requires :
     [ requires
@@ -41,9 +38,6 @@ lib boost_burl
      <library>/boost//capy
      <library>/boost//corosio
      [ ac.check-library /boost/corosio//boost_corosio_openssl : <library>/boost/corosio//boost_corosio_openssl : ]
-     [ ac.check-library /zlib//zlib : <library>/zlib//zlib <define>BOOST_BURL_HAS_ZLIB : ]
-     [ ac.check-library /brotli//brotlidec : <library>/brotli//brotlicommon <library>/brotli//brotlidec <define>BOOST_BURL_HAS_BROTLI : ]
-     [ ac.check-library /zstd//zstd : <library>/zstd//zstd <define>BOOST_BURL_HAS_ZSTD : ]
      <library>/boost//http
      <library>/boost//json
      <library>/boost//url
@@ -53,9 +47,6 @@ lib boost_burl
      <library>/boost//capy
      <library>/boost//corosio
      [ ac.check-library /boost/corosio//boost_corosio_openssl : <library>/boost/corosio//boost_corosio_openssl : ]
-     [ ac.check-library /zlib//zlib : <library>/zlib//zlib <define>BOOST_BURL_HAS_ZLIB : ]
-     [ ac.check-library /brotli//brotlidec : <library>/brotli//brotlicommon <library>/brotli//brotlidec <define>BOOST_BURL_HAS_BROTLI : ]
-     [ ac.check-library /zstd//zstd : <library>/zstd//zstd <define>BOOST_BURL_HAS_ZSTD : ]
      <library>/boost//http
      <library>/boost//json
      <library>/boost//url

doc/modules/ROOT/pages/2.guide/2m.compression.adoc

@@ -11,21 +11,40 @@
 
 Burl can advertise the content codings it accepts and transparently decode a
 compressed response body, so `gzip`, `deflate`, `br`, and `zstd` responses
-arrive already decompressed. Decoding for each coding is compiled into the
-library when it is built with the corresponding compression library.
+arrive already decompressed. Decoding depends on the relevant Boost.Http
+service being installed in the system context.
 
-== Build Support
+== Installing the Decode Services
 
-The build detects zlib, Brotli, and zstd and enables the codings they provide:
-zlib handles `gzip` and `deflate`, Brotli handles `br`, and zstd handles
-`zstd`. The macros `BOOST_BURL_HAS_ZLIB`, `BOOST_BURL_HAS_BROTLI`, and
-`BOOST_BURL_HAS_ZSTD` indicate which codings the library was built with.
+Decoding is provided by Boost.Http and must be registered in the system context once at startup, before any clients are constructed.
+
+The decoder services are provided by the `Boost::http_brotli`, `Boost::http_zlib`, and `Boost::http_zstd` libraries. Each library is available only when Boost.Http is built with the corresponding compression library. Link the libraries for the compression formats you use, and guard the installation calls with the feature macros they define. This keeps the program portable across builds that do not include all compression libraries.
+
+[source,cpp]
+----
+// Install the available decoder services.
+[[maybe_unused]] auto& ctx = capy::get_system_context();
+
+#ifdef BOOST_HTTP_HAS_BROTLI
+http::brotli::install_decode_service(ctx);
+#endif
+
+#ifdef BOOST_HTTP_HAS_ZLIB
+http::zlib::install_inflate_service(ctx);
+#endif
+
+#ifdef BOOST_HTTP_HAS_ZSTD
+http::zstd::install_decompress_service(ctx);
+#endif
+----
+
+Burl does not link against any compression library directly. Instead, it looks up the corresponding decoder services at run time.
 
 == How It Works
 
-Every supported coding is enabled by default: the client adds it to the
-`Accept-Encoding` request header and decodes a response encoded with it. The
-configuration controls each coding individually.
+With a service installed and the corresponding setting enabled, the client adds
+that coding to the `Accept-Encoding` request header and decodes a response
+encoded with it.
 
 [source,cpp]
 ----
@@ -40,8 +59,9 @@ burl::client client(co_await capy::this_coro::executor, tls_ctx, cfg);
 
 [NOTE]
 ====
-A coding whose decoder was not compiled into the library is disabled regardless
-of the setting, since the client cannot honor what it advertises.
+A coding whose decode service is not installed when the client is constructed
+is disabled regardless of the setting, since the client cannot honor what it
+advertises.
 ====
 
 The decoding is transparent: the body you read through

doc/modules/ROOT/pages/index.adoc

@@ -36,8 +36,8 @@ non-throwing alternatives.
   timeouts and per-host caps
 * *Automatic redirects* — 301/302/303/307/308 with standards-compliant method
   changes, `Referer` handling, and credential stripping on cross-origin hops
-* *Content decoding* — transparent `gzip`, `deflate`, and `br` when the
-  corresponding decode service is installed
+* *Content decoding* — transparent `gzip`, `deflate`, `br`, and `zstd` when
+  the corresponding decode service is installed
 * *Cookies* — an RFC 6265bis jar with optional public-suffix validation, and
   persistence in the Netscape cookie file format
 * *Authentication* — Basic and Bearer, set per client or per request
@@ -90,8 +90,9 @@ Burl is a focused HTTP/1.1 client. It does not provide:
 
 Boost.Burl is built on Boost.Capy, Boost.Corosio, and Boost.Http, and uses
 Boost.URL, Boost.JSON, and Boost.System. Content decoding requires Boost.Http
-built with zlib (`gzip`, `deflate`) and brotli (`br`). Public-suffix
-validation of cookies requires libpsl.
+built with zlib (`gzip`, `deflate`), brotli (`br`), and zstd (`zstd`), with
+the corresponding decode services installed in the system context.
+Public-suffix validation of cookies requires libpsl.
 
 == Code Conventions
 

example/CMakeLists.txt

@@ -8,7 +8,12 @@
 #
 
 add_executable(burl_example_usage usage.cpp)
-target_link_libraries(burl_example_usage PRIVATE Boost::burl Boost::hash2)
+target_link_libraries(burl_example_usage PRIVATE
+    Boost::burl
+    Boost::hash2
+    $<TARGET_NAME_IF_EXISTS:Boost::http_zlib>
+    $<TARGET_NAME_IF_EXISTS:Boost::http_brotli>
+    $<TARGET_NAME_IF_EXISTS:Boost::http_zstd>)
 
 find_package(nlohmann_json QUIET)
 if (nlohmann_json_FOUND)

example/Jamfile

@@ -7,6 +7,8 @@
 # Official repository: https://github.com/cppalliance/burl
 #
 
+import ac ;
+
 lib advapi32 ;
 lib crypt32 ;
 lib gdi32 ;
@@ -16,6 +18,9 @@ project
     : requirements
       <library>/boost/burl//boost_burl
       <library>/boost/hash2//boost_hash2
+      [ ac.check-library /boost/http//boost_http_zlib : <library>/boost/http//boost_http_zlib : ]
+      [ ac.check-library /boost/http//boost_http_brotli : <library>/boost/http//boost_http_brotli : ]
+      [ ac.check-library /boost/http//boost_http_zstd : <library>/boost/http//boost_http_zstd : ]
       <target-os>windows:<library>advapi32
       <target-os>windows:<library>crypt32
       <target-os>windows:<library>gdi32

example/usage.cpp

@@ -11,6 +11,9 @@
 #include <boost/burl.hpp>
 #include <boost/capy.hpp>
 #include <boost/corosio.hpp>
+#include <boost/http/brotli.hpp>
+#include <boost/http/zlib.hpp>
+#include <boost/http/zstd.hpp>
 #include <boost/json.hpp>
 #include <boost/hash2/sha2.hpp>
 
@@ -567,6 +570,18 @@ main(int argc, char* argv[])
     corosio::io_context ioc;
     corosio::tls_context tls_ctx;
 
+    // Install avialable decoder services.
+    [[maybe_unused]] auto& ctx = capy::get_system_context();
+#ifdef BOOST_HTTP_HAS_BROTLI
+    http::brotli::install_decode_service(ctx);
+#endif
+#ifdef BOOST_HTTP_HAS_ZLIB
+    http::zlib::install_inflate_service(ctx);
+#endif
+#ifdef BOOST_HTTP_HAS_ZSTD
+    http::zstd::install_decompress_service(ctx);
+#endif
+
     capy::run_async(
         ioc.get_executor(),
         [] {},