npm-storage-package/dist/multer-storage.js

Universal cloud storage package for AWS S3, Google Cloud Storage, and Azure Blob Storage with Express.js integration

import { storageAction } from "./storageAction.js";
// Custom multer storage engine for cloud storage
export class CloudStorageEngine {
    provider;
    config;
    generateFileName;
    fileFilter;
    destination;
    fieldConfigs;
    fileSizeLimit;
    constructor(options) {
        this.provider = options.provider;
        this.config = options.config;
        this.generateFileName = options.generateFileName;
        this.fileFilter = options.fileFilter;
        this.destination = options.destination;
        this.fieldConfigs = options.fieldConfigs;
        this.fileSizeLimit = options.fileSizeLimit;
    }
    _handleFile(req, file, callback) {
        // Get field-specific configuration
        const fieldConfig = this.fieldConfigs?.[file.fieldname];
        // Apply global file filter first
        if (this.fileFilter && !this.fileFilter(req, file)) {
            return callback(new Error("File type not allowed"));
        }
        // Apply field-specific extension validation
        if (fieldConfig?.allowedExtensions) {
            const fileExtension = file.originalname.toLowerCase().split(".").pop();
            if (!fileExtension || !fieldConfig.allowedExtensions.includes(`.${fileExtension}`)) {
                return callback(new Error(`File extension not allowed for field '${file.fieldname}'. Allowed: ${fieldConfig.allowedExtensions.join(", ")}`));
            }
        }
        // Generate filename using field-specific or global generator
        let fileName;
        if (fieldConfig?.generateFileName) {
            fileName = fieldConfig.generateFileName(req, file);
        }
        else if (this.generateFileName) {
            fileName = this.generateFileName(req, file);
        }
        else {
            // Use field-specific destination or global destination
            const dest = fieldConfig?.destination ||
                (typeof this.destination === "function" ? this.destination(req, file) : this.destination) ||
                "";
            const cleanDest = dest.replace(/[\\\/]+$/, ""); // Remove trailing slashes
            fileName = cleanDest
                ? `${cleanDest}/${Date.now()}-${file.originalname}`
                : `${Date.now()}-${file.originalname}`;
        }
        // Collect file data
        const chunks = [];
        let totalSize = 0;
        file.stream.on("data", (chunk) => {
            chunks.push(chunk);
            totalSize += chunk.length;
            // Check file size limit (global or field-specific)
            const sizeLimit = this.fileSizeLimit;
            if (sizeLimit && totalSize > sizeLimit) {
                return callback(new Error(`File size exceeds limit of ${Math.round(sizeLimit / (1024 * 1024))}MB`));
            }
        });
        file.stream.on("error", (error) => {
            callback(error);
        });
        file.stream.on("end", async () => {
            try {
                // Combine all chunks into a single buffer
                const buffer = Buffer.concat(chunks, totalSize);
                // Upload to cloud storage
                const uploadedUrl = await storageAction(this.provider, "upload", this.config, {
                    fileName,
                    buffer, // Pass buffer instead of file path
                    mimeType: file.mimetype,
                });
                // Return file info that multer expects
                const fileInfo = {
                    fieldname: file.fieldname,
                    originalname: file.originalname,
                    encoding: file.encoding,
                    mimetype: file.mimetype,
                    size: totalSize,
                    destination: fieldConfig?.destination || this.destination || "",
                    filename: fileName,
                    path: uploadedUrl, // Use cloud URL as path
                    buffer,
                    cloudUrl: uploadedUrl,
                    cloudKey: fileName,
                };
                callback(null, fileInfo);
            }
            catch (error) {
                callback(error);
            }
        });
    }
    _removeFile(req, file, callback) {
        // Implement file removal from cloud storage
        if (file.cloudKey) {
            storageAction(this.provider, "delete", this.config, { key: file.cloudKey })
                .then(() => callback(null))
                .catch((error) => callback(error));
        }
        else {
            callback(null);
        }
    }
}
// Factory functions to create storage engines
export function createS3Storage(options) {
    return new CloudStorageEngine({ ...options, provider: "s3" });
}
export function createGCSStorage(options) {
    return new CloudStorageEngine({ ...options, provider: "gcs" });
}
export function createAzureStorage(options) {
    return new CloudStorageEngine({ ...options, provider: "azure" });
}
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