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    multer-azure-blob-storage
    TypeScript icon, indicating that this package has built-in type declarations

    1.0.2 • Public • Published

    Multer Azure Blob Storage

    npm version Build Status

    ES6 & Typescript friendly Multer storage engine for Azure's blob storage.

    Installation

    npm i -S multer-azure-blob-storage
    

    or

    yard add multer-azure-blob-storage
    

    Usage

    Typescript

    Leverages strong typings

    import * as multer from 'multer';
    import { MulterAzureStorage, MASNameResolver } from 'multer-azure-blob-storage';
     
    const resolveBlobName: MASNameResolver = (req: any, file: Express.Multer.File): Promise<string> => {
        return new Promise<string>((resolve, reject) => {
            const blobName: string = yourCustomLogic(req, file);
            resolve(blobName);
        });
    };
     
    export type MetadataObj = { [kstring]: string };
    const resolveMetadata: MASObjectResolver = (req: any, file: Express.Multer.File): Promise<MetadataObj> => {
        return new Promise<MetadataObj>((resolve, reject) => {
            const metadata: MetadataObj = yourCustomLogic(req, file);
            resolve(metadata);
        });
    };
     
    const azureStorage: MulterAzureStorage = new MulterAzureStorage({
        connectionString: 'DefaultEndpointsProtocol=https;AccountName=mystorageaccountname;AccountKey=wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY;EndpointSuffix=core.windows.net',
        accessKey: 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY',
        accountName: 'mystorageaccountname',
        containerName: 'documents',
        blobName: resolveBlobName,
        metadata: resolveMetadata,
        containerAccessLevel: 'blob',
        urlExpirationTime: 60
    });
     
    const upload: multer.Instance = multer({
        storage: azureStorage
    });
     
    app.post('/documents', upload.any(), (req: Request, res: Response, next: NextFunction) => {
      console.log(req.files)
      res.status(200).json(req.files)
    });

    Javascript ES6

    Common.js style imports

    const multer = require('multer')
    const MulterAzureStorage = require('multer-azure-blob-storage').MulterAzureStorage;

    E6 style imports

    import * as multer from 'multer';
    import { MulterAzureStorage } from 'multer-azure-blob-storage';

    Rest of the JS code

    const resolveBlobName = (req, file) => {
        return new Promise((resolve, reject) => {
            const blobName = yourCustomLogic(req, file);
            resolve(blobName);
        });
    };
     
    const resolveMetadata = (req, file) => {
        return new Promise((resolve, reject) => {
            const metadata = yourCustomLogic(req, file);
            resolve(metadata);
        });
    };
     
    const azureStorage = new MulterAzureStorage({
        connectionString: 'DefaultEndpointsProtocol=https;AccountName=mystorageaccountname;AccountKey=wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY;EndpointSuffix=core.windows.net',
        accessKey: 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY',
        accountName: 'mystorageaccountname',
        containerName: 'documents',
        blobName: resolveBlobName,
        metadata: resolveMetadata,
        containerAccessLevel: 'blob',
        urlExpirationTime: 60
    });
     
    const upload = multer({
        storage: azureStorage
    });
     
    app.post('/documents', upload.any(), (req, res, next) => {
      console.log(req.files)
      res.status(200).json(req.files)
    });

    More details on using upload can be found in the Multer documentation

    File information

    Multer Azure Blob Storage will return the following information in each file uploaded. This can be found in the req.files param:

    Key Description Note
    fieldname The field name/key sent in the form's post request. Added by Multer
    originalname Full original name of the file on the user's computer. Added by Multer
    encoding File encoding type. Added by Multer
    mimetype MIME type of the file. Added by Multer
    blobName Blob/file name of created blob in Azure storage.
    container Name of azure storage container where the blob/file was uploaded to.
    blobType Type of blob. From the result of call to azure's getBlobProperties() of blobService
    size Size of the blob. From the result of call to azure's getBlobProperties() of blobService
    etag Etag. From the result of call to azure's getBlobProperties() of blobService
    metadata Blob's metadata. From the result of call to azure's getBlobProperties() of blobService
    url The full url to access the uploaded blob/file.

    Configuration object

    Details of the configuration object that needs to be passed into the constructor of the MulterAzureStorage class.

    Parameter Name Type Sample Value
    connectionString string 'DefaultEndpointsProtocol=https;AccountName=mystorageaccountname;AccountKey=wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY;EndpointSuffix=core.windows.net'
    accessKey string 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY'
    accountName string 'mystorageaccountname'
    containerName string or function: MASNameResolver 'documents' or (req: any, file: Express.Multer.File) => Promise<string>
    metadata { [k: string]: string } or function: MASObjectResolver '{author: John Doe; album: ASOT}' or (req: any, file: Express.Multer.File) => Promise<{[k: string]: string}>
    blobName function: MASNameResolver (optional) (req: any, file: Express.Multer.File) => Promise<string>
    containerAccessLevel string (optional) 'blob' or 'container' or 'private'
    urlExpirationTime number (optional) 60

    For more information about the meaning of individual parameters please check Azure documentation on node.js integration.

    Defaults

    For the optional parameters in the configuration object for the MulterAzureStorage class, here are the default fallback:

    • containerAccessLevel: blob
    • urlExpirationTime: 60 minutes
    • blobName: Date.now() + '-' + uuid.v4() + path.extname(file.originalname). This results in a url safe filename that looks like '1511161727560-d83d24c8-d213-444c-ba72-316c7a858805.png'

    File naming

    The containerName can be anything you choose, as long as it's unique to the storage account and as long as it fits Azure's naming restrictions. If the container does not exist the storage engine will create it.

    The blobName in an Azure container also needs to have a unique name.

    multer-azure-blob-storage allows you to customize the containerName and blobName per request before uploading the file. This can be done by proving a MASNameResolver function in the configuation object for the desired parameter.

    const resolveName: MASNameResolver = (req: any, file: Express.Multer.File): Promise<string> => {
        return new Promise<string>((resolve, reject) => {
            // Compute containerName or blobName with your custom logic.
            const computedName: string = yourCustomLogic(req, file);
            resolve(computedName);
        });
    };

    multer-azure-blob-storage also allows you to add/customize metadata per request before uploading the file. This can be done by proving a MASObjectResolver function in the configuation object for the desired parameter.

    export type MetadataObj = { [kstring]: string };
    const resolveMetadata: MASObjectResolver = (req: any, file: Express.Multer.File): Promise<MetadataObj> => {
        return new Promise<MetadataObj>((resolve, reject) => {
            const metadata: MetadataObj = yourCustomLogic(req, file);
            resolve(metadata);
        });
    };

    Azure

    Creating a storage account

    For instructions on how to create a storage account, see the following Azure documentation.

    Credentials (Quick tips)

    Your credentials can all be obtained under the Access keys section in the storage account pane in Azure.

    The connectionString is prefered. If its not provides, please provide accessKey and accountName.

    You only need to provide one of the two access keys in the accessKey field.

    The accountName is just the name of your storage account that you've created in Azure.

    If using the MulterAzureStorage class without passing in any configuration options then the following environment variables will need to be set:

    1. AZURE_STORAGE_CONNECTION_STRING, for the connectionString.
    2. AZURE_STORAGE_ACCESS_KEY, for the accessKey.
    3. AZURE_STORAGE_ACCOUNT, for the accountName.

    Tests

    Not implemented yet

    Thanks

    All great things are built on the shoulder of giants. I want to thank my giants for lending their shoulders:

    License

    MIT

    Install

    npm i multer-azure-blob-storage

    DownloadsWeekly Downloads

    1,265

    Version

    1.0.2

    License

    MIT

    Unpacked Size

    33.4 kB

    Total Files

    9

    Last publish

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