Rust Requires Chilkat v11.5.0+

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. Rust

let _ = 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.
let sb_curl = chilkat::StringBuilder::new();
let _ = sb_curl.append_ln("curl -X POST https://api.example.com/graphql \\");
let _ = sb_curl.append_ln("  -H \"Content-Type: application/graphql; charset=utf-8\" \\");
let _ = sb_curl.append_ln("  -H \"Accept: application/json\" \\");
let _ = sb_curl.append_ln("  -d \"mutation {");
let _ = sb_curl.append_ln("  createUser(");
let _ = sb_curl.append_ln("    input: {");
let _ = sb_curl.append_ln("      name: \\\"{{name}}\\\"");
let _ = sb_curl.append_ln("      city: \\\"{{city}}\\\"");
let _ = sb_curl.append_ln("      note: \\\"{{note}}\\\"");
let _ = sb_curl.append_ln("      bio: \\\"{{bio}}\\\"");
let _ = sb_curl.append_ln("    }");
let _ = sb_curl.append_ln("  ) {");
let _ = sb_curl.append_ln("    id");
let _ = sb_curl.append_ln("    name");
let _ = sb_curl.append_ln("  }");
let _ = sb_curl.append_ln("}\"");

let curl = chilkat::HttpCurl::new();

// Provide values for variables
curl.set_var("name", "José O'Connor");
curl.set_var("city", "München");
curl.set_var("note", "He said \"Hello, world!\" — and left…");
curl.set_var("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.
let sb_raw_request = chilkat::StringBuilder::new();
if curl.to_raw_request(&sb_curl.get_as_string().unwrap_or_default(), &sb_raw_request).is_err() {
    println!("{}", curl.last_error_text());
    return;
}

println!("{}", sb_raw_request.get_as_string().unwrap_or_default());

// 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
//   }
// }