C++

curl with Variable Substitution in the Request Body

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This example demonstrates using variables located in the request body with the {{variable_name}} syntax. C++

#include <CkStringBuilder.h>
#include <CkHttpCurl.h>

void ChilkatSample(void)
    {
    bool success = false;

    // Variables can also be used within the HTTP request body.
    // Variable names are enclosed between {{ and }}

    // Here is a curl command with two variables {{name}} and {{age}} located in the data.

    // curl -X POST https://api.example.com/data \
    //   -H "Content-Type: application/json" \
    //   -d '{"name":"{{name}}","age":{{age}}}'

    CkStringBuilder sbCurl;
    sbCurl.AppendLn("curl -X POST https://api.example.com/data \\");
    sbCurl.AppendLn("  -H \"Content-Type: application/json\" \\");
    sbCurl.AppendLn("  -d '{\"name\":\"{{name}}\",\"age\":{{age}}}'");

    CkHttpCurl curl;

    // Provide values for variables.
    curl.SetVar("name","Alice");
    curl.SetVar("age","30");

    // To demonstrate how the variables are replaced, this example does not execute the curl command. 
    // Instead, it generates the raw HTTP request that would be sent if the curl command were run.
    CkStringBuilder sbRawRequest;
    success = curl.ToRawRequest(sbCurl.getAsString(),sbRawRequest);
    if (success == false) {
        std::cout << curl.lastErrorText() << "\r\n";
        return;
    }

    std::cout << sbRawRequest.getAsString() << "\r\n";

    // Output:

    // POST /data HTTP/1.1
    // Host: api.example.com
    // Content-Type: application/json
    // Content-Length: 25
    // 
    // {"name":"Alice","age":30}

    // --------------------------------------------------------------------------------------------------
    // Note: Variable substitution in the request body can be turned off by 
    // setting the EnableBodyVars property equal to false

    curl.put_EnableBodyVars(false);

    success = curl.ToRawRequest(sbCurl.getAsString(),sbRawRequest);
    if (success == false) {
        std::cout << curl.lastErrorText() << "\r\n";
        return;
    }

    std::cout << sbRawRequest.getAsString() << "\r\n";

    // The raw request with body variable substitution disable:

    // Host: api.example.com
    // Content-Type: application/json
    // Content-Length: 33
    // 
    // {"name":"{{name}}","age":{{age}}}
    }