Loader - local file

Introduction

The local file loader is an implementation of the Document Loader interface used for loading document content from the local file system. This component implements the Eino: Document Loader guide.

Features

The local file loader has the following features:

• Supports loading documents directly through file paths
• Automatically detects file types and selects the appropriate parser (ExtParser must be set)
• Retains the metadata information of the files
• Supports using the file name as the document ID

Usage

Component Initialization

The local file loader is initialized via the NewFileLoader function, with the main configuration parameters as follows:

import (
    "github.com/cloudwego/eino/components/document/loader/file"
)

func main() {
    loader, err := file.NewFileLoader(ctx, &FileLoaderConfig{
        UseNameAsID: true,                // Whether to use the file name as the document ID
        Parser:      &parser.TextParser{}, // Optional: specify a custom parser
    })
}

Configuration parameters explanation:

• UseNameAsID: Whether to use the file name as the document ID
• Parser: Document parser; if not specified, the default extension parser (ExtParser, currently only implemented TextParser) is used

Loading Documents

Documents are loaded via the Load method:

docs, err := loader.Load(ctx, document.Source{
    URI: "./path/to/document.txt",
})

After loading, the following metadata will be automatically added to the documents:

• _file_name: File name
• _extension: File extension
• _source: Full file path

Notes:

• The path must point to a file, not a directory
• The file must be readable
• If UseNameAsID is true, the file name is used as the ID for a single file; for multiple documents, fileName_index is used as the ID

Full Example Usage

Standalone Usage

package main

import (
    "context"
    
    file "github.com/cloudwego/eino-ext/components/document/loader/file"
    "github.com/cloudwego/eino/components/document"
)

func main() {
    ctx := context.Background()
    
    // Initialize the loader
    loader, err := file.NewFileLoader(ctx, &file.FileLoaderConfig{
        UseNameAsID: true,
    })
    if err != nil {
        panic(err)
    }
    
    // Load document
    docs, err := loader.Load(ctx, document.Source{
        URI: "./documents/sample.txt",
    })
    if err != nil {
        panic(err)
    }
    
    // Use document content
    for _, doc := range docs {
        println(doc.Content)
        // Access metadata
        fileName := doc.MetaData[file.MetaKeyFileName]
        extension := doc.MetaData[file.MetaKeyExtension]
        source := doc.MetaData[file.MetaKeySource]
    }
}

Related Documentation

• Eino: Document Loader guide
• Eino: Document Parser guide