📁 Dropbox File Upload API II

The Dropbox File Upload API II builds on basic file-upload functionality by introducing version control, expiration policies, and advanced lifecycle management. Users can:

• Upload new files and additional versions
• List files (with only the latest non-expired version)
• Inspect full version histories
• Download the latest or any specific version
• Revert to prior versions
• Set or remove automatic expiration dates
• Delete individual versions or entire file records

This project deepens your understanding of RESTful API design, file storage, multipart handling, in-memory state management, and robust error handling.

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New Features

• Versioning: Track multiple versions of each file, with immutable history.
• Expiration: Assign per-version TTLs so old data auto-expires.
• Revert: Roll back to any prior version, which spawns a new version entry.
• Selective Deletion: Remove single versions or wipe entire file records.
• Enhanced Edge-Case Handling: Large uploads (>100 MB), unsupported types, malformed IDs, expired resources.

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Detailed Requirements

Implement a RESTful API supporting:

1. Upload / Versioning:

   • POST /api/files/upload

2. List Files:

   • GET /api/files

3. List Versions:

   • GET /api/files/:fileId/versions

4. Download Latest:

   • GET /api/files/:fileId

5. Download Specific Version:

   • GET /api/files/:fileId/versions/:versionId

6. Revert Version:

   • POST /api/files/:fileId/versions/:versionId/revert

7. Set / Remove Expiration:

   • PATCH /api/files/:fileId/expiration

8. Delete Version:

   • DELETE /api/files/:fileId/versions/:versionId

9. Delete File:

   • DELETE /api/files/:fileId

10. Error Cases:

    • Missing or invalid file uploads
    • Invalid or non-existent IDs
    • Unsupported MIME types (e.g. .exe)
    • File size limits (100 MB)
    • Expired versions not accessible

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API Endpoints

POST /api/files/upload

Upload a new file or a new version.

• Form-Data:

  • file (required)

• JSON Body (optional):

  • fileId (string) — existing file to version
  • expiresAt (ISO 8601) — future timestamp or null

• Success (201)

  {
    "fileId": "string",
    "versionId": "string",
    "versionNumber": 1,
    "filename": "string",
    "size": 12345,
    "mimeType": "text/plain",
    "createdAt": "2025-04-06T12:00:00Z",
    "expiresAt": "2025-05-01T12:00:00Z"  // or null
  }

• Errors

  • 400 Missing file / invalid expiresAt
  • 404 fileId not found
  • 415 Unsupported media type (.exe)
  • 413 File too large (>100 MB)

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GET /api/files

List all files’ latest non-expired versions.

• Success (200)

  [
    {
      "fileId": "string",
      "filename": "string",
      "latestVersion": {
        "versionId": "string",
        "versionNumber": 2,
        "size": 23456,
        "mimeType": "image/png",
        "createdAt": "2025-04-06T13:00:00Z",
        "expiresAt": null
      }
    }
  ]

---

GET /api/files/:fileId

Download the latest version if it hasn’t expired.

• Success (200): Raw file stream (Content-Type: application/octet-stream)
• Errors: 404 Not found or expired

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GET /api/files/:fileId/versions

List all non-expired versions of a file.

• Success (200)

  [
    {
      "versionId": "string",
      "versionNumber": 1,
      "size": 12345,
      "mimeType": "text/plain",
      "createdAt": "2025-04-06T12:00:00Z",
      "expiresAt": null
    }
  ]

• Errors: 404 File not found

---

GET /api/files/:fileId/versions/:versionId

Download a specific version if it hasn’t expired.

• Success (200): Raw file stream
• Errors: 404 File or version not found / expired

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POST /api/files/:fileId/versions/:versionId/revert

Revert to a previous version (creates new version entry).

• Success (200)

  {
    "fileId": "string",
    "versionId": "string",
    "versionNumber": 3,
    "createdAt": "2025-04-06T14:00:00Z"
  }

• Errors: 404 File or version not found / expired

---

PATCH /api/files/:fileId/expiration

Set or remove expiration for the latest version.

• Body

  { "expiresAt": "2025-06-01T12:00:00Z" }  // or null

• Success (200)

  {
    "fileId": "string",
    "latestVersion": {
      "versionId": "string",
      "versionNumber": number,
      "expiresAt": "2025-06-01T12:00:00Z"  // or null
    }
  }

• Errors:

  • 400 Invalid format or past date
  • 404 File not found

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DELETE /api/files/:fileId/versions/:versionId

Delete a single version.

• Success (200)

  { "message": "Version deleted successfully" }

• Errors: 404 File or version not found

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DELETE /api/files/:fileId

Delete all versions and remove the file record.

• Success (200)

  { "message": "File and all versions deleted successfully" }

• Errors: 404 File not found