使用libcurl庫(kù)可實(shí)現(xiàn)C 中的HTTP GET請(qǐng)求，需先安裝並鏈接libcurl，然後通過(guò)curl_easy_init初始化、設(shè)置URL和回調(diào)函數(shù)接收數(shù)據(jù)、執(zhí)行請(qǐng)求並清理資源，最後編譯時(shí)鏈接-lcurl。
Making an HTTP GET request in C requires using a networking library, since the standard C library doesn't include built-in support for HTTP. One of the most common and practical ways is using libcurl , a powerful, cross-platform library for handling URLs and HTTP requests.
Install and Link libcurl
Before writing code, make sure libcurl is installed on your system.
-
Ubuntu/Debian:
sudo apt install libcurl4-openssl-dev -
macOS (with Homebrew):
brew install curl - Windows: Use vcpkg or download prebuilt binaries.
When compiling, link against the curl library using -lcurl .
Write the HTTP GET Request Code
Here's a simple example that performs an HTTP GET request and prints the response body:
#include <iostream>
#include <string>
#include <curl/curl.h>
<p>// Callback function to handle data received
size_t WriteCallback(void <em>contents, size_t size, size_t nmemb, std::string</em> output) {
size_t totalSize = size <em>nmemb;
output->append((char</em> )contents, totalSize);
return totalSize;
}</p> <p>int main() {
CURL* curl;
CURLcode res;
std::string readBuffer;</p> <pre class="brush:php;toolbar:false"><code>curl = curl_easy_init(); if (curl) { curl_easy_setopt(curl, CURLOPT_URL, "https://httpbin.org/get"); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteCallback); curl_easy_setopt(curl, CURLOPT_WRITEDATA, &readBuffer); res = curl_easy_perform(curl); if (res == CURLE_OK) { std::cout << "Response:\n" << readBuffer << std::endl; } else { std::cerr << "Request failed: " << curl_easy_strerror(res) << std::endl; } curl_easy_cleanup(curl); } else { std::cerr << "Could not initialize curl." << std::endl; } return 0;</code> }
Compile and Run
Save the code to a file (eg, get_request.cpp ) and compile it:
g get_request.cpp -o get_request -lcurlThen run:
./get_requestHandle Errors and Timeouts (Optional)
You can improve reliability by setting timeouts and checking connection issues:
- Add
curl_easy_setopt(curl, CURLOPT_TIMEOUT, 10L);for a 10-second timeout. - Use
CURLOPT_USERAGENTto set a user agent if required. - Enable SSL verification in production with proper CA bundle paths if needed.
Basically just initialize curl, set options, perform the request, and clean up. The callback collects incoming data. With libcurl, it's straightforward once set up.
以上是如何用 C 語(yǔ)言發(fā)出 HTTP GET 請(qǐng)求的詳細(xì)內(nèi)容。更多資訊請(qǐng)關(guān)注PHP中文網(wǎng)其他相關(guān)文章！
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