C++
Scenarios
To use C++ to call an API through App authentication, obtain the C++ SDK, and then call the API by referring to the API calling example.
Prerequisites
- You have obtained API calling information. For details, see Preparations.
- Install the OpenSSL library.
apt-get install libssl-dev
- Install the curl library.
apt-get install libcurl4-openssl-dev
Obtaining the SDK
Old version: Log in to the ROMA Connect console, choose API Connect > API Calling > SDKs, and download the SDK.
New version: Log in to the ROMA Connect console, choose API Connect > Credentials > SDKs, and download the SDK.
The following shows the directory structure after the decompression.
Name |
Description |
---|---|
hasher.cpp |
SDK code |
hasher.h |
|
header.h |
|
RequestParams.cpp |
|
RequestParams.h |
|
signer.cpp |
|
signer.h |
|
Makefile |
Makefile file |
main.cpp |
Sample code |
API Calling Example
- Add the following references to main.cpp:
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <curl/curl.h> #include "signer.h"
- Generate a signer and enter the key and secret of the authorized credential. For details about how to obtain the information, see Obtaining API Calling Information.
// Directly writing AK/SK in code is risky. For security, encrypt your AK/SK and store them in the configuration file or environment variables. // In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, set environment variables HUAWEICLOUD_SDK_AK and HUAWEICLOUD_SDK_SK. Signer signer(getenv("HUAWEICLOUD_SDK_AK"), getenv("HUAWEICLOUD_SDK_SK"));
- Generate a new RequestParams request, and specify the method, domain name, request URI, query strings, and request body. For details about how to obtain the information, see Obtaining API Calling Information.
RequestParams* request = new RequestParams("POST", "c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com", "/app1", "Action=ListUsers&Version=2010-05-08", "demo");
- Add the x-stage header to the request to specify the environment. Add other headers to sign as required.
request->addHeader("x-stage", "RELEASE");
- Execute the following function to add the generated headers as request variables.
signer.createSignature(request);
- Use the curl library to access the API and view the access result.
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 = (char*)malloc(1); resp_header.size = 0; struct MemoryStruct resp_body; resp_body.memory = (char*)malloc(1); resp_body.size = 0; curl_global_init(CURL_GLOBAL_ALL); curl = curl_easy_init(); curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, request->getMethod().c_str()); std::string url = "http://" + request->getHost() + request->getUri() + "?" + request->getQueryParams(); curl_easy_setopt(curl, CURLOPT_URL, url.c_str()); struct curl_slist *chunk = NULL; std::set<Header>::iterator it; for (auto header : *request->getHeaders()) { std::string headerEntry = header.getKey() + ": " + header.getValue(); printf("%s\n", headerEntry.c_str()); chunk = curl_slist_append(chunk, headerEntry.c_str()); } printf("-------------\n"); curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk); curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS, request->getPayload().c_str()); 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(); return 0; }
- Run the make command to obtain a main file, execute the file, and then view the execution result.
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.See the reply and handling status in My Cloud VOC.
For any further questions, feel free to contact us through the chatbot.
Chatbot