(JavaScript) curl with Variable Substitution in a GraphQL Request Body

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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.

Note: This example requires Chilkat v11.5.0 or greater.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var 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.
var sbCurl = new CkStringBuilder();
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("}\"");

var curl = new CkHttpCurl();

// 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.
var sbRawRequest = new CkStringBuilder();
success = curl.ToRawRequest(sbCurl.GetAsString(),sbRawRequest);
if (success == false) {
    console.log(curl.LastErrorText);
    return;
}

console.log(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
//   }
// }