What causes "Rest.Error.MethodMissing" in pentaho/pentaho-kettle?

Fix the upstream step so every row has a non-empty method value (GET, POST, PUT, DELETE, HEAD, OPTIONS, PATCH)

pentaho/pentaho-kettle · error · KettleException

Rest.Error.MethodMissing

Rest.Error.MethodMissing

Error message

Rest.Error.MethodMissing

What it means

When the REST step is configured with a dynamic method (HTTP verb read from an input field), getClient reads that field and throws a KettleException with Rest.Error.MethodMissing if the value is null or empty. The step cannot execute a request without an HTTP method.

Solutions

Fix the upstream step so every row has a non-empty method value (GET, POST, PUT, DELETE, HEAD, OPTIONS, PATCH)
Add a Filter/Stream Lookup step to route rows with empty method values away from the REST step
Check the step dialog's method-field selection points at the correct input column
Default the method upstream: replace empty values with a sensible verb via 'If field value is null' / Value Mapper

Example fix

// before
String method = row[methodIdx]; // may be empty
// after
String method = row[methodIdx] == null || row[methodIdx].isEmpty() ? "GET" : row[methodIdx];

Defensive patterns

Strategy: validation

Validate before calling

if ( meta.isDynamicMethod() ) {
  String method = data.inputRowMeta.getString( rowData, data.indexOfMethod );
  if ( method == null || method.trim().isEmpty() ) {
    throw new KettleException( "Row has empty HTTP method in field: " + data.indexOfMethod );
  }
}

Try / catch

try {
  Object[] out = step.callRest( row );
} catch ( KettleException e ) {
  if ( e.getMessage() != null && e.getMessage().contains( "MethodMissing" ) ) {
    log.error( "HTTP method field is empty for row — check upstream step", e );
  }
}

Prevention

Guarantee the method column is populated for every row (use a default via Value Mapper or If-null step)
Preview the transformation to confirm the method field index selected in the dialog is correct
Filter out or dead-letter rows lacking a method before the REST step
Avoid whitespace-only values — trim the field upstream

When it happens

Trigger: Transformations with 'Dynamic method' enabled where the method field in the incoming row is empty or null for a given row.

Common situations: Upstream step failed to populate the method column; rows from heterogeneous sources where some rows lack a method; user selected the wrong field index in the step dialog.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/9264f98cb97f0b1b. Report an issue: GitHub.

Appendix: source

Thrown at plugins/rest/core/src/main/java/org/pentaho/di/trans/steps/rest/Rest.java:97

    try ( Client client = getClient( rowData ) ) {
      WebTarget target = buildRequest( client, rowData );
      return invokeRequest( target, rowData );
    } catch ( Exception e ) {
      throw new KettleException( BaseMessages.getString( PKG, "Rest.Error.CanNotReadURL", data.realUrl ), e );
    }
  }

  protected Client getClient( Object[] rowData ) throws KettleException {
    // get dynamic url ?
    if ( meta.isUrlInField() ) {
      data.realUrl = data.inputRowMeta.getString( rowData, data.indexOfUrlField );
    }

    // get dynamic method?
    if ( meta.isDynamicMethod() ) {
      data.method = data.inputRowMeta.getString( rowData, data.indexOfMethod );
      if ( Utils.isEmpty( data.method ) ) {
        throw new KettleException( BaseMessages.getString( PKG, "Rest.Error.MethodMissing" ) );
      }
    }

    if ( isDetailed() ) {
      logDetailed( BaseMessages.getString( PKG, "Rest.Log.ConnectingToURL", data.realUrl ) );
    }

    // Register a custom StringMessageBodyWriter to solve PDI-17423
    ClientBuilder clientBuilder = ClientBuilder.newBuilder();
    clientBuilder.withConfig( data.config ).property( HttpUrlConnectorProvider.SET_METHOD_WORKAROUND, true );

    if ( meta.isIgnoreSsl() || !Utils.isEmpty( data.trustStoreFile ) ) {
      clientBuilder.sslContext( data.sslContext );
      clientBuilder.hostnameVerifier( ( s1, s2 ) -> true );
    }

    Client client = clientBuilder.build();
    if ( data.basicAuthentication != null ) {

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