Depart

Caution

Depart is in a pre-release state and is subject to frequent breaking changes. Merge requests will be ignored and issues are disabled until v1.0.0, the first production ready release.

Synopsis

Depart is express middleware for handling multipart/form-data. It is also usable as a standalone request processor.

Features

• Strongly typed via TypeScript
• Promises & async/await friendly.
• Supports streaming each file to multiple storage methods simultaneously, without the need to store on disk first.

Installation

$ npm install --save depart

Storage

Depart's storage system is very robust and accomodates many different use cases. Please study the scenarios outlined in the Storage Modules & onFile guide before beginning implementation.

Usage

Depart can be used as a standalone class, or it can be used as express middleware.

Standalone Processing

The DepartRequestProcessor class is what is used to parse incoming formData request and can be used independently of express. Begin by importing and instantiating, optionally passing an options object implementing the DepartConfig interface specified in the Models section of this readme.

This use case is ideal for non-express platforms, or for dynamically changing the configuration in each endpoint or request.

parse

This is the primary method of DepartRequestProcessor. It parses all fields and files of a request and returns a DepartFormData object which is defined in the Models section of this readme.

Express Middleware

Depart can also be used as middleware. When utilized in this fashion, the incoming express request will have a formData property attached to it which will be of type DepartFormData.

In the express configuration file, instantiate an instance of DepartExpressMiddleware, passing an object of type DepartConfig. Then use the instance's handleRequest method as middleware. Example below:

const formDataParser = new DepartRequestProcessor({
    ...,
    storage: [...],
    onFile: {
        ...
    }
})

app.use(formDataParser.handleRequest.bind(formDataParser));

Models

DepartFormData

    fields?: {
        [key: string]: string;
    },
    files?: {
        [key: string]: DepartStoredFile[];
    }

Note that all values of fields will be of type string. It is up to the consuming app to handle conversions and further processing.

DepartFile

{
    fieldName: string;
    originalName?: string;
    encoding?: string;
    mimeType?: string;
}

• fieldName - The field in the request that contained the file

• originalName - The file's name as set in the form data

• encoding - The file's encoding

• mimeType - The specified mime type of the file

DepartStoredFile

DepartStoredFile extends DepartFile {
    storage: {
        setup: any,
        result: any;
    }
}

DepartConfig

    fileFields?: string[] | {
        [fieldName: string]: DepartFileFieldConfig;
    };

    storage?: IStorageModule | IStorageModule[];

    onField?: (fieldName: string, value: string) => Promise<any>;
    onFile?: (file: DepartFile) => Promise<(boolean | Object)[])>;
    onFileStored?: (file: DepartStoredFile) => Promise<void>;

    preservePaths?: boolean;

    limits?: {
        fieldNameSize?: number;
        fieldSize?: number;
        fields?: number;
        fileSize?: number;
        files?: number;
        parts?: number;
        headerPairs?: number;
    };

• fileFields - Defines the fields in the request that will contain files. If value is an array of field names, Depart will error if a file exists in an unspecified field. For a more granular configuration, reference the DepartFileFieldConfig model. When omitted, any uploaded file is processed without restrictions. Not specifying this property can pose a security risk and is only recommended in specified use cases

• storage - Specifies the storage module, or multiple storage modules, that will handle each file. See IStorageModule model definition for more information (Default: MemoryStorage)

• onField - Called when a field is encountered in the form data. If return value is a promise resolving to false, further processing of the formData will be terminated.

• onFile - Called when a file is encountered in the form data and is responsible for setting up storage of the file. See the Storage Module section for more information.

• onFileStored - Called after a file is stored successfully. See the Storage Module section for more information.

• preservePath - Passed to Busboy. If paths in the multipart 'fileName' field shall be preserved. (Default: false).

• limits - Passed to Busboy. These apply to the entire request and are not field specific

  • fieldNameSize - Max field name size (in bytes) (Default: 100 bytes).

  • fieldSize - Max field value size (in bytes) (Default: 1MB).

  • fields - Max number of non-file fields (Default: Infinity).

  • fileSize - For multipart forms, the max file size (in bytes) (Default: Infinity).

  • files - For multipart forms, the max number of file fields (Default: Infinity).

  • parts - For multipart forms, the max number of parts (fields + files) (Default: Infinity).

  • headerPairs - For multipart forms, the max number of header key=>value pairs to parse Default: 2000 (same as node's http).

DepartFileFieldConfig

maxFiles?: number;
requireUniqueOriginalName?: boolean;

• maxFiles - If specified, indicates the maximum number of files allowed in this field. Recommended this be set to avoid DDOS attacks. Requests exceeding this limit will error.

• requireUniqueOriginalName - If true, files with the same file name will be rejected with an error.

License

MIT