使用 C++ REST SDK 进行网络编程
安装 C++ REST SDK
$ brew install cpprestsdk
$ brew install boost
$ brew install libressl
创建工程
打开 Xcode，File / New / Project...
在向导的第1页选 macOS / Command Line Tool
在向导的第2页语言选 C++，Product Name 填上任意名称
在向导的第3页选择任意文件夹，点击 Create 创建工程。
配置工程
将 System Header Search Paths 设置为
/usr/local/Cellar/cpprestsdk/2.10.2/include
/usr/local/Cellar/boost/1.67.0_1/include
/usr/local/Cellar/libressl/2.7.4/include
将 Library Search Paths 设置为
/usr/local/Cellar/cpprestsdk/2.10.2/lib
/usr/local/Cellar/boost/1.67.0_1/lib
/usr/local/Cellar/libressl/2.7.4/lib
将 Other Linker Flags 设置为
-lcpprest -lboost_system -lboost_thread-mt -lboost_chrono-mt -lssl -lcrypto
cpprestsdk: Undefined symbols for architecture x86_64
示例代码1
#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
using namespace utility; // Common utilities like string conversions
using namespace web; // Common features like URIs.
using namespace web::http; // Common HTTP functionality
using namespace web::http::client; // HTTP client features
using namespace concurrency::streams; // Asynchronous streams
int main(int argc, char* argv[])
{
auto fileStream = std::make_shared<ostream>();
// Open stream to output file.
pplx::task<void> requestTask = fstream::open_ostream(U("results.html")).then([=](ostream outFile) {
*fileStream = outFile;
// Create http_client to send the request.
http_client client(U("http://www.bing.com/"));
// Build request URI and start the request.
uri_builder builder(U("/search"));
builder.append_query(U("q"), U("cpprestsdk github"));
return client.request(methods::GET, builder.to_string());
})
// Handle response headers arriving.
.then([=](http_response response) {
printf("Received response status code:%u\n", response.status_code());
// Write response body into the file.
return response.body().read_to_end(fileStream->streambuf());
})
// Close the file stream.
.then([=](size_t) {
return fileStream->close();
});
// Wait for all the outstanding I/O to complete and handle any exceptions
try {
requestTask.wait();
} catch (const std::exception &e) {
printf("Error exception:%s\n", e.what());
}
return 0;
}
这段代码访问
http://www.bing.com/search?q=cpprestsdk github
将结果保存为 results.html。
JSON : Placeholder
JSON : Placeholder (https://jsonplaceholder.typicode.com/) 是一个用于测试的 REST API 网站。
以下使用 C++ REST SDK 调用该网站的 REST API，获取字符串以及 JSON 数据。
- GET /posts/1
- GET /posts
- POST /posts
- PUT /posts/1
- DELETE /posts/1
所有 GET API 都返回JSON数据，格式（JSON-Schema）如下：
{
"type":"object",
"properties": {
"userId": {"type" : "integer"},
"id": {"type" : "integer"},
"title": {"type" : "string"},
"body": {"type" : "string"}
}
}
示例代码2
#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
#include <cpprest/json.h>
#include <boost/algorithm/string/replace.hpp>
using namespace utility; // Common utilities like string conversions
using namespace web; // Common features like URIs.
using namespace web::http; // Common HTTP functionality
using namespace web::http::client; // HTTP client features
using namespace concurrency::streams; // Asynchronous streams
using namespace std;
static void print_results(json::value const & value)
{
if(!value.is_null()) {
auto userId = value.at(U("userId")).as_integer();
auto id = value.at(U("id")).as_integer();
auto title = value.at(U("title")).as_string();
auto body = boost::algorithm::replace_all_copy(value.at(U("body")).as_string(), "\n", "\\n");
cout << "Post {userId = " << userId
<< ", id = " << id
<< ", title = \"" << title
<< "\", body = \"" << body
<< "\"}" << endl;
}
}
static void json_get()
{
http_client client(U("https://jsonplaceholder.typicode.com/"));
// Build request URI and start the request.
uri_builder builder(U("posts/1"));
client
// send the HTTP GET request asynchronous
.request(methods::GET, builder.to_string())
// continue when the response is available
.then([](http_response response) -> pplx::task<json::value> {
// if the status is OK extract the body of the response into a JSON value
// works only when the content type is application\json
if(response.status_code() == status_codes::OK) {
return response.extract_json();
}
// return an empty JSON value
return pplx::task_from_result(json::value());
})
// continue when the JSON value is available
.then([](pplx::task<json::value> previousTask) {
// get the JSON value from the task and display content from it
try {
json::value const & v = previousTask.get();
print_results(v);
} catch (http_exception const & e) {
printf("Error exception:%s\n", e.what());
}
})
.wait();
}
static void json_post()
{
http_client client(U("https://jsonplaceholder.typicode.com/"));
json::value json_v ;
json_v["userId"] = json::value::number(101);
json_v["title"] = json::value::string("test title");
json_v["body"] = json::value::string("test body");
client
.request(methods::POST, U("posts"), json_v)
.then([](http_response response) -> pplx::task<string_t> {
if(response.status_code() == status_codes::Created) {
return response.extract_string();
}
return pplx::task_from_result(string_t());
})
.then([](pplx::task<string_t> previousTask) {
try {
string_t const & v = previousTask.get();
cout << v << endl;
} catch (http_exception const & e) {
printf("Error exception:%s\n", e.what());
}
})
.wait();
}
static void json_update()
{
http_client client(U("https://jsonplaceholder.typicode.com/"));
json::value json_v ;
json_v["userId"] = json::value::number(101);
json_v["title"] = json::value::string("test title");
json_v["body"] = json::value::string("test body");
client
.request(methods::PUT, U("posts/1"), json_v)
.then([](http_response response) -> pplx::task<string_t> {
if(response.status_code() == status_codes::OK) {
return response.extract_string();
}
return pplx::task_from_result(string_t());
})
.then([](pplx::task<string_t> previousTask) {
try {
string_t const & v = previousTask.get();
cout << v << endl;
} catch (http_exception const & e) {
printf("Error exception:%s\n", e.what());
}
})
.wait();
}
static void json_delete()
{
http_client client(U("https://jsonplaceholder.typicode.com/"));
client
.request(methods::DEL, U("posts/1"))
.then([](http_response response) -> pplx::task<string_t> {
if(response.status_code() == status_codes::OK) {
return response.extract_string();
}
return pplx::task_from_result(string_t());
})
.then([](pplx::task<string_t> previousTask) {
try {
string_t const & v = previousTask.get();
cout << v << endl;
} catch (http_exception const & e) {
printf("Error exception:%s\n", e.what());
}
})
.wait();
}
int main(int argc, char* argv[])
{
json_get();
json_post();
json_update();
json_delete();
return 0;
}
这段代码调用4个 REST API
然后打印所返回的 JSON 数据以及字符串的内容
Post {userId = 1, id = 1, title = "sunt aut facere repellat provident occaecati excepturi optio reprehenderit", body = "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"}
{
"body": "test body",
"title": "test title",
"userId": 101,
"id": 101
}
{
"body": "test body",
"title": "test title",
"userId": 101,
"id": 1
}
{}
