webcc

同学们，【中文版】在这里！

Lightweight C++ HTTP client and server library based on Boost Asio.

Please turn to our Wiki (under construction) for more tutorials and guides.

Wondering how to build Webcc? Check Build Instructions.

Git repo: https://github.com/sprinfall/webcc. Please check this one instead of the forked for the latest features.

Features

• Cross-platform: Linux, Windows and Mac
• Easy-to-use client API inspired by Python requests
• SSL/HTTPS support with OpenSSL (optional)
• GZip compression support with Zlib (optional)
• Persistent (Keep-Alive) connections
• Data streaming
  • for uploading and downloading large files on client
  • for serving and receiving large files on server
• Basic & Token authorization
• Timeout control
• Source code follows Google C++ Style
• Automation tests and unit tests included
• No memory leak detected by VLD
• etc.

Client API

Let's start from a complete client example:

#include <iostream>

#include "webcc/client_session.h"
#include "webcc/logger.h"

int main() {
  // Configure logger to print only to console.
  WEBCC_LOG_INIT("", webcc::LOG_CONSOLE);
  
  // Session provides convenient request APIs, stores request configurations
  // and manages persistent connenctions.
  webcc::ClientSession session;

  // Catch exceptions for error handling.
  try {
    // Send a HTTP GET request.
    auto r = session.Get("http://httpbin.org/get");

    // Print the response data.
    std::cout << r->data() << std::endl;

  } catch (const webcc::Error& error) {
    std::cerr << error << std::endl;
  }

  return 0;
}

The Get() method is nothing but a shortcut of Request(). Using Request() directly is more complicated:

auto r = session.Request(webcc::RequestBuilder{}.Get("http://httpbin.org/get")());

As you can see, a helper class named RequestBuilder is used to chain the parameters and finally build a request object. Please pay attention to the () operator.

Both the shortcut and Request() accept URL query parameters:

// Query parameters are passed using a std::vector. 
session.Get("http://httpbin.org/get", { "key1", "value1", "key2", "value2" });

session.Request(webcc::RequestBuilder{}.
                Get("http://httpbin.org/get").
                Query("key1", "value1").
                Query("key2", "value2")
                ());

Adding additional headers is also easy:

session.Get("http://httpbin.org/get",
            {"key1", "value1", "key2", "value2"},
            {"Accept", "application/json"});  // Also a std::vector
                
session.Request(webcc::RequestBuilder{}.
                Get("http://httpbin.org/get").
                Query("key1", "value1").
                Query("key2", "value2").
                Header("Accept", "application/json")
                ());

Accessing HTTPS has no difference from HTTP:

session.Get("https://httpbin.org/get");

NOTE: The HTTPS/SSL support requires the build option WEBCC_ENABLE_SSL to be enabled.

Listing GitHub public events is not a big deal:

auto r = session.Get("https://api.github.com/events");

You can then parse r->data() to JSON object with your favorite JSON library. My choice for the examples is jsoncpp. But Webcc itself doesn't understand JSON nor require one. It's up to you to choose the most appropriate JSON library.

The shortcuts (Get(), Post(), etc.) are easier to use but RequestBuilder is more powerful. It provides a lot of functions for you to customize the request. Let's see more examples.

In order to list the followers of an authorized GitHub user, you need either Basic Authorization:

session.Request(webcc::RequestBuilder{}.
                Get("https://api.github.com/user/followers").
                AuthBasic(login, password)  // Should be replaced by real login and password
                ());

Or Token Authorization:

session.Request(webcc::RequestBuilder{}.
                Get("https://api.github.com/user/followers").
                AuthToken(token)  // Should be replaced by a valid token
                ());

Though Keep-Alive (i.e., persistent connection) is a good feature and enabled by default, you can turn it off:

auto r = session.Request(webcc::RequestBuilder{}.
                         Get("http://httpbin.org/get").
                         KeepAlive(false)  // No Keep-Alive
                         ());

The API for other HTTP requests is no different from GET.

POST request needs a body which is normally a JSON string for REST API. Let's post a small UTF-8 encoded JSON string:

session.Request(webcc::RequestBuilder{}.
                Post("http://httpbin.org/post").
                Body("{'name'='Adam', 'age'=20}").
                Json().Utf8()
                ());

Webcc has the ability to stream large response data to a file. This is especially useful when downloading files.

auto r = session.Request(webcc::RequestBuilder{}.
                         Get("http://httpbin.org/image/jpeg")(),
                         true);  // !!!

// Move the streamed file to your destination.
r->file_body()->Move("./wolf.jpeg");

Please check the examples for more information.

Server API

Hello, World!

class HelloView : public webcc::View {
public:
  webcc::ResponsePtr Handle(webcc::RequestPtr request) override {
    if (request->method() == "GET") {
      return webcc::ResponseBuilder{}.OK().Body("Hello, World!")();
    }

    return {};
  }
};

int main() {
  try {
    webcc::Server server(8080);

    server.Route("/", std::make_shared<HelloView>());

    server.Run();

  } catch (const std::exception&) {
    return 1;
  }

  return 0;
}

Book Store

Suppose you want to create a book server and provide the following operations with RESTful API:

• Query books based on some criterias.
• Add a new book.
• Get the detailed information of a book.
• Update the information of a book.
• Delete a book.

The first two operations are implemented by BookListView deriving from webcc::View:

class BookListView : public webcc::View {
public:
  webcc::ResponsePtr Handle(webcc::RequestPtr request) override {
    if (request->method() == "GET") {
      return Get(request);
    }

    if (request->method() == "POST") {
      return Post(request);
    }

    return {};
  }
  
private:
  // Get a list of books based on query parameters.
  webcc::ResponsePtr Get(webcc::RequestPtr request);

  // Create a new book.
  // The new book's data is attached as request data in JSON format.
  webcc::ResponsePtr Post(webcc::RequestPtr request);
};

Other operations are implemented by BookDetailView:

// The URL is like '/books/{BookID}', and the 'args' parameter contains
// the matched book ID.
class BookDetailView : public webcc::View {
public:
  webcc::ResponsePtr Handle(webcc::RequestPtr request) override {
    if (request->method() == "GET") {
      return Get(request);
    }

    if (request->method() == "PUT") {
      return Put(request);
    }

    if (request->method() == "DELETE") {
      return Delete(request);
    }

    return {};
  }
  
protected:
  // Get the detailed information of a book.
  webcc::ResponsePtr Get(webcc::RequestPtr request);

  // Update a book.
  webcc::ResponsePtr Put(webcc::RequestPtr request);

  // Delete a book.
  webcc::ResponsePtr Delete(webcc::RequestPtr request);
};

The detailed implementation is out of the scope of this README, but here is an example:

webcc::ResponsePtr BookDetailView::Get(webcc::RequestPtr request) {
  if (request->args().size() != 1) {
    // NotFound means the resource specified by the URL cannot be found.
    // BadRequest could be another choice.
    return webcc::ResponseBuilder{}.NotFound()();
  }

  const std::string& book_id = request->args()[0];

  // Get the book by ID from, e.g., the database.
  // ...

  if (<NotFound>) {
    // There's no such book with the given ID. 
    return webcc::ResponseBuilder{}.NotFound()();
  }

  // Convert the book to JSON string and set as response data.
  return webcc::ResponseBuilder{}.OK().Data(<JsonStringOfTheBook>).
      Json().Utf8()();
}

Last step, route URLs to the proper views and run the server:

int main(int argc, char* argv[]) {
  // ...

  try {
    webcc::Server server(8080);

    server.Route("/books",
                 std::make_shared<BookListView>(),
                 { "GET", "POST" });

    server.Route(webcc::R("/books/(\\d+)"),
                 std::make_shared<BookDetailView>(),
                 { "GET", "PUT", "DELETE" });

    server.Run();

  } catch (const std::exception& e) {
    std::cerr << e.what() << std::endl;
    return 1;
  }

  return 0;

Please see examples/rest_book_server.cc for more details.