C#

curl with Variable Substitution in a GraphQL Request Body

See more CURL Examples

This example shows how to use variables inside a graphql request body using the {{variable_name}} syntax. When the HTTP request’s Content-Type indicates graphql, Chilkat automatically applies proper escaping to each substituted value, ensuring the resulting graphql remains valid. C#

bool success = false;

success = false;

//  Variable names are enclosed between {{ and }}
//  Important: Variables should be placed inside the quotes.

//  curl -X POST https://api.example.com/graphql \
//    -H "Content-Type: application/graphql; charset=utf-8" \
//    -H "Accept: application/json" \
//    --data-binary "mutation {
//    createUser(
//      input: {
//        name: \"{{name}}\"
//        city: \"{{city}}\"
//        note: \"{{note}}\"
//        bio: \"{{bio}}\"
//      }
//    ) {
//      id
//      name
//    }
//  }"

//  Build the above curl command.
Chilkat.StringBuilder sbCurl = new Chilkat.StringBuilder();
sbCurl.AppendLn("curl -X POST https://api.example.com/graphql \\");
sbCurl.AppendLn("  -H \"Content-Type: application/graphql; charset=utf-8\" \\");
sbCurl.AppendLn("  -H \"Accept: application/json\" \\");
sbCurl.AppendLn("  -d \"mutation {");
sbCurl.AppendLn("  createUser(");
sbCurl.AppendLn("    input: {");
sbCurl.AppendLn("      name: \\\"{{name}}\\\"");
sbCurl.AppendLn("      city: \\\"{{city}}\\\"");
sbCurl.AppendLn("      note: \\\"{{note}}\\\"");
sbCurl.AppendLn("      bio: \\\"{{bio}}\\\"");
sbCurl.AppendLn("    }");
sbCurl.AppendLn("  ) {");
sbCurl.AppendLn("    id");
sbCurl.AppendLn("    name");
sbCurl.AppendLn("  }");
sbCurl.AppendLn("}\"");

Chilkat.HttpCurl curl = new Chilkat.HttpCurl();

//  Provide values for variables
curl.SetVar("name","José O'Connor");
curl.SetVar("city","München");
curl.SetVar("note","He said \"Hello, world!\" — and left…");
curl.SetVar("bio","Loves sushi, café visits, and π ≈ 3.14159");

//  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.
Chilkat.StringBuilder sbRawRequest = new Chilkat.StringBuilder();
success = curl.ToRawRequest(sbCurl.GetAsString(),sbRawRequest);
if (success == false) {
    Debug.WriteLine(curl.LastErrorText);
    return;
}

Debug.WriteLine(sbRawRequest.GetAsString());

//  The output is shown below.
//  Notice the quote chars around "Hello, world!" are properly escaped.

//  POST /graphql HTTP/1.1
//  Accept: application/json
//  Host: api.example.com
//  Content-Type: application/graphql; charset=utf-8
//  Content-Length: 250
//  
//  mutation {
//    createUser(
//      input: {
//        name: "José O'Connor"
//        city: "München"
//        note: "He said \"Hello, world!\" — and left…"
//        bio: "Loves sushi, café visits, and π ≈ 3.14159"
//      }
//    ) {
//      id
//      name
//    }
//  }