FlowiseAI/Flowise · error · Error

Unsupported source type: ${block.source_type}

Error message

Unsupported source type: ${block.source_type}

What it means

Thrown at the end of fromStandardImageBlock (line 161) after the only two recognized source_type values ('url' and 'base64') have been checked. Any other source_type for a standard image block reaches this terminal throw.

Source

Thrown at packages/components/nodes/chatmodels/ChatGoogleGenerativeAI/FlowiseChatGoogleGenerativeAI.ts:161

                    }
                } else {
                    return {
                        fileData: {
                            mimeType: block.mime_type ?? '',
                            fileUri: block.url
                        }
                    }
                }
            }
            if (block.source_type === 'base64') {
                return {
                    inlineData: {
                        mimeType: block.mime_type ?? '',
                        data: block.data
                    }
                }
            }
            throw new Error(`Unsupported source type: ${block.source_type}`)
        },

        fromStandardAudioBlock(block): FileDataPart | InlineDataPart {
            if (!isMultimodalModel) {
                throw new Error('This model does not support audio')
            }
            if (block.source_type === 'url') {
                const data = parseBase64DataUrl({ dataUrl: block.url })
                if (data) {
                    return {
                        inlineData: {
                            mimeType: data.mime_type,
                            data: data.data
                        }
                    }
                } else {
                    return {
                        fileData: {

View on GitHub (pinned to abe4a8601a)

Solutions

1. Normalize image blocks to source_type 'url' (with block.url) or 'base64' (with block.data) before sending to the Gemini node.
2. Use LangChain's standard DataContentBlock helpers to construct blocks so the source_type is always valid.
3. Log block.source_type upstream to catch the offending producer.

Example fix

// before (throws): { type:'image', source_type:'file', path:'/x.png' }
// after:           { type:'image', source_type:'base64', mime_type:'image/png', data: base64String }

const ALLOWED_IMG_SOURCE = new Set(['url', 'base64'])
function validImageSources(parts: any[]): boolean {
  return parts.filter((p) => p?.type === 'image').every((p) => ALLOWED_IMG_SOURCE.has(p.source_type))
}
if (!validImageSources(allParts)) throw new Error('image blocks must use source_type url|base64')

type StdImageBlock =
  | { type: 'image'; source_type: 'url'; url: string; mime_type?: string }
  | { type: 'image'; source_type: 'base64'; data: string; mime_type?: string }
function isStdImageBlock(c: unknown): c is StdImageBlock {
  if (typeof c !== 'object' || c === null || (c as any).type !== 'image') return false
  const st = (c as any).source_type
  return (st === 'url' && typeof (c as any).url === 'string')
      || (st === 'base64' && typeof (c as any).data === 'string')
}

try {
  return convertToProviderContentBlock(block, converter)
} catch (e) {
  if (e instanceof Error && /Unsupported source type/.test(e.message)) {
    // normalize block.source_type to 'url' or 'base64' and retry
  }
  throw e
}

When it happens

Trigger: A standard image content block whose source_type is neither 'url' nor 'base64' (e.g., 'file', 'path', 'stream', undefined-but-not-matching).

Common situations: A custom content producer invents a source_type, a schema migration renamed the field, or a DataContentBlock from another provider is passed through without normalization.

Related errors

• Please provide image as base64 encoded data URL
• Invalid media content
• This model does not support images
• Unknown content type ${content.type}
• Unknown content ${JSON.stringify(content)}

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/af73421ca6eea47c. Report an issue: GitHub.