janhq/jan · error · RagError

UnsupportedFileType

UnsupportedFileType

Error message

Unsupported file type: {0}

What it means

RagError::UnsupportedFileType is raised when the RAG plugin is asked to ingest a document whose file type/extension is not among the supported parsers (displayed as "Unsupported file type: {0}" with the offending type). The plugin intentionally rejects unknown formats instead of guessing.

Solutions

1. Check the file extension/MIME type against the plugin's supported list before calling ingest.
2. Convert the document to a supported format (e.g. export .docx to PDF or plain text) first.
3. Filter or skip unsupported files during batch ingestion with a clear user notice.
4. Extend the plugin's parser set if a new format is genuinely required.

Example fix

// before: blind ingest
for f in files { rag.ingest(f)?; }

// after
const SUPPORTED: [&str; 2] = ["pdf", "txt"];
for f in files {
    let ext = f.extension().and_then(|e| e.to_str()).unwrap_or("");
    if !SUPPORTED.contains(&ext) {
        eprintln!("skipping {f:?}: unsupported type .{ext}");
        continue;
    }
    rag.ingest(f)?;
}

// Rust: check extension against supported set before ingest
fn is_supported(path: &Path) -> bool {
    matches!(path.extension().and_then(|e| e.to_str()), Some("pdf") | Some("txt"))
}

fn as_unsupported_type(err: &RagError) -> Option<&str> {
    match err { RagError::UnsupportedFileType(t) => Some(t), _ => None }
}

match rag.ingest(file) {
    Err(RagError::UnsupportedFileType(t)) => {
        notify_user(format!(".{t} files are not supported; convert to PDF or TXT"));
    }
    other => other?,
}

When it happens

Trigger: Calling the RAG ingest API with files like .docx, .xlsx, images, or arbitrary binaries when only formats such as .pdf/.txt are supported.

Common situations: Users dropping unsupported files into an upload UI; batch-importing a folder containing mixed file types; filename extensions changed to disguise binary content.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Failed to parse document
• IO error
• IoError
• ParseError
• Unsupported file type

AI-assisted analysis of janhq/jan@7205d770c1 (2026-09-17). Data as JSON: /api/errors/d727972133f1ba05. Report an issue: GitHub.

Appendix: source

Thrown at src-tauri/plugins/tauri-plugin-rag/src/error.rs:8

use serde::{Deserialize, Serialize};

#[derive(Debug, thiserror::Error, Serialize, Deserialize)]
pub enum RagError {
    #[error("Failed to parse document: {0}")]
    ParseError(String),

    #[error("Unsupported file type: {0}")]
    UnsupportedFileType(String),

    #[error("IO error: {0}")]
    IoError(String),
}

impl From<std::io::Error> for RagError {
    fn from(err: std::io::Error) -> Self {
        RagError::IoError(err.to_string())
    }
}

View on GitHub (pinned to 7205d770c1)