Replace curlpp with cpp-httplib by jiuker · Pull Request #257 · minio/minio-cpp

jiuker · 2026-08-19T05:47:20Z

Background

The SDK's HTTP layer was built on curlpp, a C++ wrapper over libcurl. That brings two problems:

Complicated build process — curlpp is not a header-only library, so every build path (vcpkg manifest, distro packages, source fallback for Alpine/musl) must compile and link it, along with libcurl itself. See Migrate HTTP client to cpp-httplib to simplify build process #256 for the migration request.
Latency and rigidity — the curlpp/curl pipeline adds overhead and makes fine-grained control of the request lifecycle harder than needed.

What this PR does

Replaces curlpp with cpp-httplib (yhirose/cpp-httplib):

Header-only: no compiled dependency, no libcurl — the build no longer needs curl/curlpp at all (vcpkg manifest, CMake resolution and the Alpine source-fallback path are updated accordingly).
Same behavior, preserved across the port:
- streaming receive into the data function (S3 Select event stream, GetObject, ListenBucketNotification, DownloadObject);
- upload/download progress reporting, including the final average-speed report the multipart path depends on;
- SSL settings (verify toggle, CA bundle override, client certificates), total-transfer timeout semantics, stall guard, disabled 100-continue handshake;
- debug flag wired to httplib's logger;
- the unused DataFunctionArgs::handle (a curlpp transfer handle) is dropped.
Simpler API surface: http.h no longer exposes curlpp types.

Dependencies after this PR

vcpkg: cpp-httplib, inih, nlohmann-json, openssl, pugixml, zlib (Windows only). Alpine builds need no libcurl.

Validation

Full test suite against MinIO (sync + async Select, notification, multipart upload with progress, download round-trips) — green locally and in CI across Ubuntu, arm64, Windows MSVC, macOS and Alpine/musl.

Summary by CodeRabbit

Improvements
- Updated HTTP handling for more reliable requests, streaming, timeouts, cancellation, and TLS verification.
- Improved URI encoding and decoding for object names, tags, paths, and query parameters.
- Enhanced compatibility across Alpine Linux, macOS, and Windows platforms.
Documentation
- Updated build instructions and dependency guidance for the HTTP implementation.
Maintenance
- Refined example output formatting without changing behavior.
- Improved platform-specific build configuration and dependency setup.

replace curlapp by httplib

coderabbitai · 2026-08-19T05:47:31Z

No actionable comments were generated in the recent review. 🎉

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📒 Files selected for processing (6)

cmake/miniocpp-deps.cmake
src/args.cc
src/client.cc
src/http.cc
src/response.cc
vcpkg.json

💤 Files with no reviewable changes (2)

src/args.cc
src/response.cc

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📝 Walkthrough

Walkthrough

The PR replaces curlpp with cpp-httplib for HTTP requests, adds local URI encoding helpers, updates dependency resolution and platform wiring, and removes curlpp-specific response handling.

Changes

cpp-httplib migration

Layer / File(s)	Summary
Dependency and platform wiring `.github/workflows/ci.yml`, `cmake/...`, `CMakeLists.txt`, `vcpkg.json`, `README.md`, `CLAUDE.md`	Build configuration, Alpine packages, manifest entries, and documentation now use cpp-httplib. Apple frameworks and OpenSSL support are configured.
URI encoding contract `include/miniocpp/utils.h`, `src/utils.cc`, `src/args.cc`, `src/response.cc`	Adds `UriEncode` and `UriDecode`. Request paths, query parameters, and URL-encoded listing values use the new helpers.
HTTP transport replacement `include/miniocpp/http.h`, `src/http.cc`, `src/client.cc`, `src/args.cc`, `src/response.cc`	Replaces curlpp request execution, callbacks, parsing, cancellation, and error handling with cpp-httplib operations.
API compatibility and serialization cleanup `include/miniocpp/client.h`, `src/client.cc`, `src/baseclient.cc`, `src/types.cc`, `examples/*`	Adds Windows `GetObject` macro protection and reformats unchanged XML and example output expressions.

Estimated code review effort: 4 (Complex) | ~60 minutes

Merge Risk: 🟠 High · up to d9beb

The HTTP migration can mishandle failed requests by sending S3 error responses through data handlers, which may hide useful errors or corrupt downloaded content; unresolved dependency configuration issues may also break some fallback or TLS builds. These issues should be fixed or explicitly accepted before merging.

Sequence Diagram(s)

sequenceDiagram
  participant Request
  participant HttpClient
  participant Response
  Request->>HttpClient: Configure endpoint, TLS, headers, and timeouts
  Request->>HttpClient: Execute HTTP method
  HttpClient->>Response: Provide status, headers, body, and progress
  Response-->>Request: Return result or HTTP error

Poem

I hop through headers, light and bright,
Replacing curlpp in the night.
Paths now encode with careful flair,
Alpine finds its packages there.
cpp-httplib leads the way—
A bunny builds a greener day.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 4.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the primary change: replacing curlpp with cpp-httplib.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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cicd

encode

refactor

SelectObjectContent is a POST with a data function, but only GET wired the content receiver, so the response body (the S3 Select event stream) was dropped and records never reached the handler. Stream POST responses to the data function too. httplib discards the response when a receiver cancels; GET captures the status up front via the response handler, POST has no such hook in httplib 0.51/0.53, so on a caller-initiated cancel report success (the caller ended the transfer itself).

httplib loads macOS system certificates from the Keychain (SecTrustSettingsCopyCertificates); the vcpkg httplib target does not link the Security framework, so miniocpp fails to link on macOS. Add the frameworks httplib's own CMake uses (CFNetwork, CoreFoundation, Security).

Drop the unused content_provider, use a reference for the httplib client, and trim verbose comments to the essentials.

The handle field was the curlpp transfer handle; the httplib backend has no equivalent and nothing reads it, so remove the field and its constructor parameters.

An explicit SSL_CERT_FILE must re-enable certificate verification even when IGNORE_CERT_CHECK is set, matching the curl backend (the CA file overrides the ignore flag). The httplib port only set the CA path and left verification disabled.

- Honor the debug flag via httplib's logger (was dead). - Use set_max_timeout for the caller-set timeout: it is a total transfer deadline like the old CURLOPT_TIMEOUT, whereas read/write timeouts only bound single operations. - Report average upload/download speeds in a final progress call, as the curl backend did (the multipart progress wrapper depends on it). - Send an empty Expect header to disable the 100-continue handshake.

The http.h description, the dependency list and the Alpine notes still named curlpp after the httplib migration.

cpp-httplib is header-only and does not need libcurl; remove curl-dev from the Alpine CI install list and README instructions.

windows.h (pulled in by httplib) maps GetObject to GetObjectA, which renamed the member definition in client.cc and broke MSVC with C2509. Undo the macro at the declaration and definition sites.

httplib reports progress as size_t; cast to double explicitly for the ProgressFunctionArgs fields.

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Inline comments:
In `@cmake/miniocpp-deps.cmake`:
- Around line 36-52: The cpp-httplib dependency setup must fetch remote tags
before checking out the pinned version. In the existing block around
MINIO_CPP_HTTPLIB_PINNED_TAG and the checkout execute_process call, run git
fetch --quiet --tags origin in the repository before the checkout, handle fetch
failure consistently, and preserve the v0.53.1 pin.

In `@src/client.cc`:
- Around line 720-722: Update the RDMA lifetime comment near
ScopedRDMARegistration to state that args.buf remains registered only for the
request/use_rdma block and is deregistered when that scope exits; remove the
claim that it stays pinned for the process lifetime.

In `@src/http.cc`:
- Line 327: Remove the per-request body_str copy in the PutObject and UploadPart
request paths, and call the appropriate httplib Put/Post overload with the
existing body.data() pointer and body.size() length. Preserve the current
request payload and content type while avoiding allocation or copying of the
upload body.
- Around line 313-334: Update the content_receiver and response_handler flow in
the relevant request overloads so non-2xx response chunks are buffered into
response.body while preserving datafunc delivery and cancellation behavior; keep
successful 2xx bodies streamed without buffering. Apply the same status-aware
buffering to the POST overload by using an overload that exposes the response
status or checking the status within the receiver, and ensure BaseClient
receives error XML while DownloadObject does not write it as a successful
download body.
- Around line 335-365: Require cpp-httplib version 0.53.0 or newer in both the
CMake find_package(httplib) and pkg_check_modules(... cpp-httplib) discovery
paths, while retaining the pinned v0.53.1 fallback so older releases cannot be
selected.

In `@src/response.cc`:
- Around line 20-21: Remove the httplib.h include from the response translation
unit because response decoding now uses utils::UriDecode and no longer
references httplib symbols. Leave HTTP-related includes confined to the
implementation that uses them, such as the http translation unit.

Apply the same fix in `@src/args.cc` around lines 20 - 21: Same unused include and
same remediation.

In `@vcpkg.json`:
- Line 8: Update the cpp-httplib dependency declaration in vcpkg.json to enable
its openssl feature, so the imported httplib::httplib target carries the
matching HTTPS configuration while preserving the existing dependency
declaration.

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Push a commit to this branch (recommended)
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📒 Files selected for processing (18)

.github/workflows/ci.yml
CLAUDE.md
CMakeLists.txt
README.md
cmake/miniocpp-deps.cmake
examples/GetBucketTags.cc
examples/GetObjectTags.cc
include/miniocpp/client.h
include/miniocpp/http.h
include/miniocpp/utils.h
src/args.cc
src/baseclient.cc
src/client.cc
src/http.cc
src/response.cc
src/types.cc
src/utils.cc
vcpkg.json

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- Buffer non-2xx response bodies instead of streaming them to the data function, so error payloads reach the caller (GET gates on the status via the response handler; POST overloads have none, so Select streams and surfaces errors through the event stream). - Avoid copying the upload body: use the char*/size overloads for PUT and plain POST; only the Select POST (small SQL body) still copies. - Require cpp-httplib >= 0.51 (vcpkg port version) in find_package and pkg-config, and fetch tags before checkout of the pinned source tag. - Enable the openssl feature in vcpkg.json. - Drop unused httplib includes from response.cc and args.cc; fix the RDMA registration lifetime comment.

replace curlapp by httplib

873cf5c

replace curlapp by httplib

jiuker added 10 commits August 19, 2026 13:49

cicd

012b2b4

cicd

tag

17b1691

encode

c19c292

encode

Update client.cc

6ada432

refactor

b4db317

refactor

lint

d853ace

http: simplify the httplib port

70bb871

Drop the unused content_provider, use a reference for the httplib client, and trim verbose comments to the essentials.

http: drop the unused DataFunctionArgs::handle

1bd2d61

The handle field was the curlpp transfer handle; the httplib backend has no equivalent and nothing reads it, so remove the field and its constructor parameters.

jiuker force-pushed the replace-curlapp-by-httplib branch from 1ff16f3 to 1bd2d61 Compare August 19, 2026 10:23

jiuker added 4 commits August 19, 2026 18:27

docs: drop the last curlpp references

1256d63

The http.h description, the dependency list and the Alpine notes still named curlpp after the httplib migration.

alpine: drop the libcurl dependency

39475ee

cpp-httplib is header-only and does not need libcurl; remove curl-dev from the Alpine CI install list and README instructions.

jiuker changed the title ~~replace curlapp by httplib~~ Replace curlpp with cpp-httplib Aug 19, 2026

jiuker added 2 commits August 19, 2026 18:55

win: keep Client::GetObject clear of the windows.h macro

2af4a67

windows.h (pulled in by httplib) maps GetObject to GetObjectA, which renamed the member definition in client.cc and broke MSVC with C2509. Undo the macro at the declaration and definition sites.

http: silence -Wconversion on progress bytes

a0f5fb9

httplib reports progress as size_t; cast to double explicitly for the ProgressFunctionArgs fields.

jiuker marked this pull request as ready for review August 19, 2026 11:19

coderabbitai Bot requested changes Aug 19, 2026

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Comment thread cmake/miniocpp-deps.cmake

Comment thread src/client.cc Outdated

Comment thread src/http.cc

Comment thread src/http.cc Outdated

Comment thread src/http.cc

Comment thread src/response.cc Outdated

Comment thread vcpkg.json Outdated

jiuker added 2 commits August 19, 2026 21:20

http: fix receiver lambda formatting

d9beb16

coderabbitai Bot approved these changes Aug 19, 2026

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harshavardhana approved these changes Aug 20, 2026

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harshavardhana merged commit 2f3aefa into minio:main Aug 20, 2026
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This was referenced Aug 20, 2026

Migrate HTTP client to cpp-httplib to simplify build process #256

Closed

How do I close the progress bar #227

Closed

remove incorrect usage of curls Multi API #185

Closed

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Replace curlpp with cpp-httplib - #257

Replace curlpp with cpp-httplib#257
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What this PR does

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