Delphi ActiveX 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. Delphi ActiveX

var
success: Integer;
sbCurl: TChilkatStringBuilder;
curl: TChilkatHttpCurl;
sbRawRequest: TChilkatStringBuilder;

begin
success := 0;

success := 0;

//  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.
sbCurl := TChilkatStringBuilder.Create(Self);
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('}"');

curl := TChilkatHttpCurl.Create(Self);

//  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.
sbRawRequest := TChilkatStringBuilder.Create(Self);
success := curl.ToRawRequest(sbCurl.GetAsString(),sbRawRequest.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(curl.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(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
//    }
//  }