更新时间:2023-02-16 GMT+08:00
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C

操作场景

使用C语言调用APP认证的API时,您需要先获取SDK,参考API调用示例调用API。

准备环境

  1. 已获取API的域名、请求url、请求方法、AppKey和AppSecret等信息,具体参见认证前准备
  2. 安装openssl库。
    apt-get install libssl-dev
  3. 安装curl库。
    apt-get install libcurl4-openssl-dev

获取SDK

下载SDK的最新版本,获取“ApiGateway-c-sdk.zip”压缩包,解压后目录结构如下:

名称

说明

signer_common.c

SDK代码

signer_common.h

signer.c

signer.h

Makefile

Makefile文件

main.c

示例代码

调用API示例

  1. 在main.c中加入以下引用。

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <curl/curl.h>
    #include "signer.h"

  2. 生成一个sig_params_t类型的变量,填入AppKey和AppSecret。

    sig_params_t params;
    sig_params_init(&params);
    sig_str_t app_key = sig_str("4f5f626b-073f-402f-a1e0-e52171c6100c");
    sig_str_t app_secret = sig_str("******");
    params.key = app_key;
    params.secret = app_secret;

  3. 指定方法名、域名、请求uri、查询字符串和body。

    sig_str_t host = sig_str("c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com");
    sig_str_t method = sig_str("GET");
    sig_str_t uri = sig_str("/app1");
    sig_str_t query_str = sig_str("a=1&b=2");
    sig_str_t payload = sig_str("");
    params.host = host;
    params.method = method;
    params.uri = uri;
    params.query_str = query_str;
    params.payload = payload;

  4. 给请求添加x-stage头,内容为环境名。如果有需要,添加需要签名的其他头域。

    sig_headers_add(&params.headers, "x-stage", "RELEASE");

  5. 进行签名,执行此函数会将生成的签名头加入request变量中。

    sig_sign(&params);

  6. 使用curl库访问API,查看访问结果。

    static size_t
    WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp)
    {
        size_t realsize = size * nmemb;
        struct MemoryStruct *mem = (struct MemoryStruct *)userp;
    
        mem->memory = (char*)realloc(mem->memory, mem->size + realsize + 1);
        if (mem->memory == NULL) {
            /* out of memory! */
            printf("not enough memory (realloc returned NULL)\n");
            return 0;
        }
    
        memcpy(&(mem->memory[mem->size]), contents, realsize);
        mem->size += realsize;
        mem->memory[mem->size] = 0;
    
        return realsize;
    }
    
    //send http request using curl library
    int perform_request(RequestParams* request)
    {
        CURL *curl;
        CURLcode res;
        struct MemoryStruct resp_header;
        resp_header.memory = malloc(1);
        resp_header.size = 0;
        struct MemoryStruct resp_body;
        resp_body.memory = malloc(1);
        resp_body.size = 0;
    
        curl_global_init(CURL_GLOBAL_ALL);
        curl = curl_easy_init();
    
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, params.method.data);
        char url[1024];
        sig_snprintf(url, 1024, "http://%V%V?%V", &params.host, &params.uri, &params.query_str);
        curl_easy_setopt(curl, CURLOPT_URL, url);
        struct curl_slist *chunk = NULL;
        for (int i = 0; i < params.headers.len; i++) {
            char header[1024];
            sig_snprintf(header, 1024, "%V: %V", &params.headers.data[i].name, &params.headers.data[i].value);
            printf("%s\n", header);
            chunk = curl_slist_append(chunk, header);
        }
        printf("-------------\n");
        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, params.payload.data);
        curl_easy_setopt(curl, CURLOPT_NOBODY, 0L);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
        curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void *)&resp_header);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&resp_body);
        //curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
        res = curl_easy_perform(curl);
        if (res != CURLE_OK) {
            fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
        }
        else {
            long status;
            curl_easy_getinfo(curl, CURLINFO_HTTP_CODE, &status);
            printf("status %d\n", status);
            printf(resp_header.memory);
            printf(resp_body.memory);
        }
        free(resp_header.memory);
        free(resp_body.memory);
        curl_easy_cleanup(curl);
    
        curl_global_cleanup();
    
        //free signature params
        sig_params_free(&params);
        return 0;
    }

  7. 运行make命令编译,得到可执行文件main,执行main文件,查看结果。
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