Refine multipart form.

examples/file_upload_client.cc

@@ -55,7 +55,7 @@ int main(int argc, char* argv[]) {
     auto r = session.Request(webcc::HttpRequestBuilder{}.Post().
                              Url(url).
                              File("file", upload_dir / "remember.txt").
-                             Form("text", "text default")
+                             Form("json", "{}", "application/json")
                              ());
 
     //std::cout << r->content() << std::endl;

examples/file_upload_server.cc

@@ -11,12 +11,12 @@ class FileUploadService : public webcc::RestService {
 public:
   void Handle(const webcc::RestRequest& request,
               webcc::RestResponse* response) final {
-    if (request.http->method() == webcc::http::methods::kPost) {
+    if (request.http->method() == "POST") {
       std::cout << "files: " << request.http->form_parts().size() << std::endl;
 
-      for (auto& file : request.http->form_parts()) {
-        std::cout << "name: " << file.name() << std::endl;
-        std::cout << "data: " << std::endl << file.data() << std::endl;
+      for (auto& part : request.http->form_parts()) {
+        std::cout << "name: " << part.name() << std::endl;
+        std::cout << "data: " << std::endl << part.data() << std::endl;
       }
 
       response->content = "OK";

webcc/common.cc

@@ -15,6 +15,8 @@ namespace webcc {
 
 namespace misc_strings {
 
+// Literal strings can't be used because they have an extra '\0'.
+
 const char HEADER_SEPARATOR[] = { ':', ' ' };
 const char CRLF[] = { '\r', '\n' };
 
@@ -210,8 +212,8 @@ bool ContentDisposition::Init(const std::string& str) {
 // -----------------------------------------------------------------------------
 
 FormPart::FormPart(const std::string& name, const Path& path,
-                   const std::string& mime_type)
-    : name_(name), mime_type_(mime_type) {
+                   const std::string& media_type)
+    : name_(name), media_type_(media_type) {
   if (!ReadFile(path, &data_)) {
     throw Exception(kFileIOError, "Cannot read the file.");
   }
@@ -220,50 +222,61 @@ FormPart::FormPart(const std::string& name, const Path& path,
   // TODO: encoding
   file_name_ = path.filename().string(std::codecvt_utf8<wchar_t>());
 
-  // Determine content type from file extension.
-  if (mime_type_.empty()) {
+  // Determine media type from file extension.
+  if (media_type_.empty()) {
     std::string extension = path.extension().string();
-    mime_type_ = http::media_types::FromExtension(extension, false);
+    media_type_ = http::media_types::FromExtension(extension, false);
   }
 }
 
 FormPart::FormPart(const std::string& name, std::string&& data,
-                   const std::string& mime_type)
-    : name_(name), data_(std::move(data)), mime_type_(mime_type) {
+                   const std::string& media_type)
+    : name_(name), data_(std::move(data)), media_type_(media_type) {
 }
 
-void FormPart::Prepare(std::vector<boost::asio::const_buffer>& payload) {
+void FormPart::Prepare(Payload* payload) {
+  // The payload buffers don't own the memory.
+  // It depends on some existing variables/objects to keep the memory.
+  // That's why we need |headers_|.
   if (headers_.empty()) {
-    std::string value = "form-data";
-    if (!name_.empty()) {
-      value.append("; name=\"" + name_ + "\"");
-    }
-    if (!file_name_.empty()) {
-      value.append("; filename=\"" + file_name_ + "\"");
-    }
-    headers_.Set(http::headers::kContentDisposition, value);
-
-    if (!mime_type_.empty()) {
-      headers_.Set(http::headers::kContentType, mime_type_);
-    }
+    SetHeaders();
   }
 
   using boost::asio::buffer;
 
   for (const HttpHeader& h : headers_.data()) {
-    payload.push_back(buffer(h.first));
-    payload.push_back(buffer(misc_strings::HEADER_SEPARATOR));
-    payload.push_back(buffer(h.second));
-    payload.push_back(buffer(misc_strings::CRLF));
+    payload->push_back(buffer(h.first));
+    payload->push_back(buffer(misc_strings::HEADER_SEPARATOR));
+    payload->push_back(buffer(h.second));
+    payload->push_back(buffer(misc_strings::CRLF));
   }
 
-  payload.push_back(buffer(misc_strings::CRLF));
+  payload->push_back(buffer(misc_strings::CRLF));
 
   if (!data_.empty()) {
-    payload.push_back(buffer(data_));
+    payload->push_back(buffer(data_));
+  }
+
+  payload->push_back(buffer(misc_strings::CRLF));
+}
+
+void FormPart::SetHeaders() {
+  // Header: Content-Disposition
+
+  std::string content_disposition = "form-data";
+  if (!name_.empty()) {
+    content_disposition.append("; name=\"" + name_ + "\"");
   }
+  if (!file_name_.empty()) {
+    content_disposition.append("; filename=\"" + file_name_ + "\"");
+  }
+  headers_.Set(http::headers::kContentDisposition, content_disposition);
+
+  // Header: Content-Type
 
-  payload.push_back(buffer(misc_strings::CRLF));
+  if (!media_type_.empty()) {
+    headers_.Set(http::headers::kContentType, media_type_);
+  }
 }
 
 }  // namespace webcc

webcc/common.h

@@ -151,16 +151,23 @@ private:
 
 // -----------------------------------------------------------------------------
 
-// Form data part.
+// A part of the multipart form data.
 class FormPart {
 public:
   FormPart() = default;
 
+  // Construct a file part.
+  // The file name will be extracted from path.
+  // The media type, if not provided, will be inferred from file extension.
   FormPart(const std::string& name, const Path& path,
-           const std::string& mime_type = "");
+           const std::string& media_type = "");
 
+  // Construct a non-file part.
+  // The data will be moved, no file name is needed.
+  // The media type is optional. If the data is a JSON string, you can specify
+  // media type as "application/json".
   FormPart(const std::string& name, std::string&& data,
-           const std::string& mime_type = "");
+           const std::string& media_type = "");
 
 #if WEBCC_DEFAULT_MOVE_COPY_ASSIGN
 
@@ -172,7 +179,7 @@ public:
   FormPart(FormPart&& rhs)
       : name_(std::move(rhs.name_)),
         file_name_(std::move(rhs.file_name_)),
-        mime_type_(std::move(rhs.mime_type_)),
+        media_type_(std::move(rhs.media_type_)),
         data_(std::move(rhs.data_)) {
   }
 
@@ -180,7 +187,7 @@ public:
     if (&rhs != this) {
       name_ = std::move(rhs.name_);
       file_name_ = std::move(rhs.file_name_);
-      mime_type_ = std::move(rhs.mime_type_);
+      media_type_ = std::move(rhs.media_type_);
       data_ = std::move(rhs.data_);
     }
     return *this;
@@ -188,53 +195,74 @@ public:
 
 #endif  // WEBCC_DEFAULT_MOVE_COPY_ASSIGN
 
+  // API: SERVER
   const std::string& name() const {
     return name_;
   }
 
+  // API: SERVER/PARSER
   void set_name(const std::string& name) {
     name_ = name;
   }
 
+  // API: SERVER
   const std::string& file_name() const {
     return file_name_;
   }
 
+  // API: SERVER/PARSER
   void set_file_name(const std::string& file_name) {
     file_name_ = file_name;
   }
 
-  const std::string& mime_type() const {
-    return mime_type_;
+  // API: SERVER
+  const std::string& media_type() const {
+    return media_type_;
   }
 
+  // API: SERVER
   const std::string& data() const {
     return data_;
   }
 
+  // API: SERVER/PARSER
   void AppendData(const std::string& data) {
     data_.append(data);
   }
 
-  void AppendData(const char* data, std::size_t size) {
-    data_.append(data, size);
+  // API: SERVER/PARSER
+  void AppendData(const char* data, std::size_t count) {
+    data_.append(data, count);
   }
 
-  void Prepare(Payload& payload);
+  // API: CLIENT
+  void Prepare(Payload* payload);
 
 private:
+  // Generate headers from properties.
+  void SetHeaders();
+
+private:
+  // The <input> name within the original HTML form.
+  // E.g., given HTML form:
+  //   <input name="file1" type="file">
+  // the name will be "file1".
   std::string name_;
 
-  // E.g., example.jpg
-  // TODO: Unicode
+  // The original local file name.
+  // E.g., "baby.jpg".
   std::string file_name_;
 
-  // E.g., image/jpeg
-  std::string mime_type_;
+  // The content-type if the media type is known (e.g., inferred from the file
+  // extension or operating system typing information) or as
+  // application/octet-stream.
+  // E.g., "image/jpeg".
+  std::string media_type_;
 
+  // Headers generated from the above properties.
+  // Only Used to prepare payload.
   HttpHeaders headers_;
 
-  // Binary file data.
   std::string data_;
 };
 

webcc/http_message.cc

@@ -13,6 +13,8 @@ namespace webcc {
 
 namespace misc_strings {
 
+// Literal strings can't be used because they have an extra '\0'.
+
 const char HEADER_SEPARATOR[] = { ':', ' ' };
 const char CRLF[] = { '\r', '\n' };
 

webcc/http_request.cc

@@ -9,6 +9,8 @@ namespace webcc {
 
 namespace misc_strings {
 
+// Literal strings can't be used because they have an extra '\0'.
+
 const char CRLF[] = { '\r', '\n' };
 const char DOUBLE_DASHES[] = { '-', '-' };
 
@@ -27,49 +29,50 @@ void HttpRequest::Prepare() {
 
   if (form_parts_.empty()) {
     HttpMessage::Prepare();
-  } else {
-    // Multipart form data.
-
-    // Another choice to generate the boundary is what Apache does.
-    // See: https://stackoverflow.com/a/5686863
-    if (boundary_.empty()) {
-      boundary_ = RandomUuid();
-    }
+    return;
+  }
 
-    SetContentType("multipart/form-data; boundary=" + boundary_);
+  // Multipart form data.
 
-    Payload data_payload;
+  // Another choice to generate the boundary is like what Apache does.
+  // See: https://stackoverflow.com/a/5686863
+  if (boundary_.empty()) {
+    boundary_ = RandomUuid();
+  }
 
-    using boost::asio::buffer;
+  SetContentType("multipart/form-data; boundary=" + boundary_);
 
-    for (auto& part : form_parts_) {
-      // Boundary
-      data_payload.push_back(buffer(misc_strings::DOUBLE_DASHES));
-      data_payload.push_back(buffer(boundary_));
-      data_payload.push_back(buffer(misc_strings::CRLF));
+  Payload data_payload;
 
-      part.Prepare(data_payload);
-    }
+  using boost::asio::buffer;
 
-    // Boundary end
+  for (auto& part : form_parts_) {
+    // Boundary
     data_payload.push_back(buffer(misc_strings::DOUBLE_DASHES));
     data_payload.push_back(buffer(boundary_));
-    data_payload.push_back(buffer(misc_strings::DOUBLE_DASHES));
     data_payload.push_back(buffer(misc_strings::CRLF));
 
-    // Update Content-Length header.
-    std::size_t content_length = 0;
-    for (auto& buffer : data_payload) {
-      content_length += buffer.size();
-    }
-    SetContentLength(content_length);
+    part.Prepare(&data_payload);
+  }
 
-    // Prepare start line and headers.
-    HttpMessage::Prepare();
+  // Boundary end
+  data_payload.push_back(buffer(misc_strings::DOUBLE_DASHES));
+  data_payload.push_back(buffer(boundary_));
+  data_payload.push_back(buffer(misc_strings::DOUBLE_DASHES));
+  data_payload.push_back(buffer(misc_strings::CRLF));
 
-    // Append payload of content data.
-    payload_.insert(payload_.end(), data_payload.begin(), data_payload.end());
+  // Update Content-Length header.
+  std::size_t content_length = 0;
+  for (auto& buffer : data_payload) {
+    content_length += buffer.size();
   }
+  SetContentLength(content_length);
+
+  // Prepare start line and headers.
+  HttpMessage::Prepare();
+
+  // Append payload of content data.
+  payload_.insert(payload_.end(), data_payload.begin(), data_payload.end());
 }
 
 void HttpRequest::CreateStartLine() {

webcc/http_request_builder.h

@@ -1,7 +1,6 @@
 #ifndef WEBCC_HTTP_REQUEST_BUILDER_H_
 #define WEBCC_HTTP_REQUEST_BUILDER_H_
 
-#include <map>
 #include <string>
 #include <vector>