Feature/multipart headers

[kwach]

• feature: additional field: header - providing access to headers per form-data part
• UT test provided

Note: Google Test filter = MultipartFormDataTest.AccessPartHeaders
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from MultipartFormDataTest
[ RUN      ] MultipartFormDataTest.AccessPartHeaders
[       OK ] MultipartFormDataTest.AccessPartHeaders (1004 ms)
[----------] 1 test from MultipartFormDataTest (1004 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (1004 ms total)
[  PASSED  ] 1 test.

[yhirose]

@kwach could you please run clang-format? (You don't have to worry about the 'abidiff/abi' error.
https://github.com/yhirose/cpp-httplib/actions/runs/15518234423/job/43688499197?pr=2152

[kwach]

@kwach could you please run clang-format? (You don't have to worry about the 'abidiff/abi' error. https://github.com/yhirose/cpp-httplib/actions/runs/15518234423/job/43688499197?pr=2152

heh, ok. I've enabled workflows on my fork and now it passes. I'm just learnig about workflows, sorry :D

[yhirose]

Could you explain why handled is needed?

[kwach]

I reused code from the MultipartFormDataTest

[kwach]

then there is

ASSERT_TRUE(handled);

in

auto se = detail::scope_exit([&] {...}

[kwach]

[==========] 365 tests from 88 test suites ran. (272323 ms total)
[  PASSED  ] 365 tests.

  YOU HAVE 2 DISABLED TESTS

[yhirose]

Thanks for your fine contribution!

[yhirose]

@kwach after this pr has been merged, we now get lots of warnings when compiling test/test.cc.

test.cc:3939:39: warning: missing field 'headers' initializer [-Wmissing-field-initializers]
 3939 |       {"text1", "text default", "", ""},
      |                                       ^

The current code looks as below.

TEST_F(ServerTest, MultipartFormData) {
 MultipartFormDataItems items = {
     {"text1", "text default", "", ""},
     {"text2", "aωb", "", ""},
     {"file1", "h\ne\n\nl\nl\no\n", "hello.txt", "text/plain"},
     {"file2", "{\n  \"world\", true\n}\n", "world.json", "application/json"},
     {"file3", "", "", "application/octet-stream"},
     {"file4", "", "", "   application/json  tmp-string    "}};

 auto res = cli_.Post("/multipart", items);

 ASSERT_TRUE(res);
 EXPECT_EQ(StatusCode::OK_200, res->status);
}

In order to fix these warnings, we have to add {}...

TEST_F(ServerTest, MultipartFormData) {
 MultipartFormDataItems items = {
     {"text1", "text default", "", "", {}},
     {"text2", "aωb", "", "", {}},
     {"file1", "h\ne\n\nl\nl\no\n", "hello.txt", "text/plain", {}},
     {"file2", "{\n  \"world\", true\n}\n", "world.json", "application/json", {}},
     {"file3", "", "", "application/octet-stream", {}},
     {"file4", "", "", "   application/json  tmp-string    ", {}}};

 auto res = cli_.Post("/multipart", items);

 ASSERT_TRUE(res);
 EXPECT_EQ(StatusCode::OK_200, res->status);
}

The headers fields is useful on the server side, but it looks weird on the client side. It's because the client isn't interested in the headers field at all, but a call needs to set {} to the MultipartFormData object when we use the initializer syntax.

We may need to add a comment like this:

struct MultipartFormData {
  std::string name;
  std::string content;
  std::string filename;
  std::string content_type;
  
  // for server use only
  Headers headers;
};

I'll think more about how to deal with this issue.