Upload by FriendsOfFlarum

An extension that handles file uploads intelligently for your forum.

Features

For images:
- Auto watermarks.
- Auto resizing.
Mime type to upload adapter mapping.
Whitelisting mime types.
Uploading on different storage services (local, imgur, AWS S3 for instance).
Drag and drop uploads.
Uploading multiple files at once (button and drag and drop both support this).
Easily extendable, the extension heavily relies on Events.
Extender interface to disable or force particular adapters (see below)

Installation

Install manually:

composer require fof/upload:"*"

Updating

composer require fof/upload:"*"
php flarum migrate
php flarum cache:clear

Configuration

Enable the extension, a new tab will appear on the left hand side. This separate settings page allows you to further configure the extension.

On new installations, a pre-defined regex will be inserted for you that enables image uploads, restricted to safe image types. We now include SVG as safe, due to our SVG sanitization method. Default image types allowed are:

JPEG
PNG
GIF
WebP
AVIF
BMP
TIFF
SVG

The regex for these types is ^image\/(jpeg|png|gif|webp|avif|bmp|tiff|svg\+xml)$, and can be modified as required. We STRONGLY discourage the use of a wildcard such as ^image\/.*, as this could introduce vulnerabilities in the uploaded files. Versions of fof/upload prior to 1.8.0 used this as default, and is considered insecure.

Make sure you configure the upload permission on the permissions page as well.

Storage Configuration

FoF Upload supports configuration via both the admin panel (database settings) and environment variables. Environment variables take precedence over database settings when configured.

Environment Variable Configuration

You can configure storage adapters using environment variables, which is particularly useful for:

Docker/containerized deployments
CI/CD pipelines
Multi-environment setups (dev/staging/production)
Keeping credentials out of the database

AWS S3 / S3-Compatible Storage

To configure S3 via environment variables, set all four required variables:

# Required (all 4 must be set)
FOF_UPLOAD_AWS_S3_KEY=your-access-key
FOF_UPLOAD_AWS_S3_SECRET=your-secret-key
FOF_UPLOAD_AWS_S3_BUCKET=your-bucket-name
FOF_UPLOAD_AWS_S3_REGION=us-east-1

# Optional
FOF_UPLOAD_AWS_S3_ACL=public-read                    # Object ACL (public-read, private, etc.)
FOF_UPLOAD_AWS_S3_ENDPOINT=https://s3.example.com    # For S3-compatible services (MinIO, Wasabi, etc.)
FOF_UPLOAD_AWS_S3_PATH_STYLE_ENDPOINT=true           # Required for MinIO and some S3-compatible services
FOF_UPLOAD_AWS_S3_CUSTOM_URL=https://cdn.example.com # Custom domain for your bucket
FOF_UPLOAD_CDN_URL=https://cdn.example.com           # CDN URL for serving files

IAM Role Authentication (EC2/ECS/EKS):

For environments with IAM roles (EC2 instances, ECS tasks, EKS pods), you can omit credentials:

# Required for IAM mode
FOF_UPLOAD_AWS_S3_BUCKET=your-bucket-name
FOF_UPLOAD_AWS_S3_REGION=us-east-1
FOF_UPLOAD_AWS_S3_USE_IAM=true  # Enable IAM role authentication

# Optional (same as above)
FOF_UPLOAD_AWS_S3_ACL=public-read
FOF_UPLOAD_CDN_URL=https://cdn.example.com

When FOF_UPLOAD_AWS_S3_USE_IAM=true, credentials are not required and the AWS SDK will automatically use the instance/pod IAM role.

Important Notes:

Traditional mode: All 4 variables (KEY, SECRET, BUCKET, REGION) must be set
IAM mode: Only BUCKET, REGION, and USE_IAM=true are required
If any required variable is missing, the extension falls back to database settings
Environment variables always override database settings when fully configured

S3-Compatible Services

LocalStack (local development):

FOF_UPLOAD_AWS_S3_KEY=test
FOF_UPLOAD_AWS_S3_SECRET=test
FOF_UPLOAD_AWS_S3_BUCKET=uploads
FOF_UPLOAD_AWS_S3_REGION=us-east-1
FOF_UPLOAD_AWS_S3_ENDPOINT=http://localhost:4566
FOF_UPLOAD_AWS_S3_PATH_STYLE_ENDPOINT=true  # Required for LocalStack!

MinIO (self-hosted):

FOF_UPLOAD_AWS_S3_KEY=minioadmin
FOF_UPLOAD_AWS_S3_SECRET=minioadmin
FOF_UPLOAD_AWS_S3_BUCKET=uploads
FOF_UPLOAD_AWS_S3_REGION=us-east-1
FOF_UPLOAD_AWS_S3_ENDPOINT=https://minio.example.com
FOF_UPLOAD_AWS_S3_PATH_STYLE_ENDPOINT=true  # Required for MinIO!

DigitalOcean Spaces:

FOF_UPLOAD_AWS_S3_KEY=your-spaces-key
FOF_UPLOAD_AWS_S3_SECRET=your-spaces-secret
FOF_UPLOAD_AWS_S3_BUCKET=your-space-name
FOF_UPLOAD_AWS_S3_REGION=nyc3
FOF_UPLOAD_AWS_S3_ENDPOINT=https://nyc3.digitaloceanspaces.com

Wasabi:

FOF_UPLOAD_AWS_S3_KEY=your-wasabi-key
FOF_UPLOAD_AWS_S3_SECRET=your-wasabi-secret
FOF_UPLOAD_AWS_S3_BUCKET=your-bucket
FOF_UPLOAD_AWS_S3_REGION=us-east-1
FOF_UPLOAD_AWS_S3_ENDPOINT=https://s3.wasabisys.com

Backblaze B2:

FOF_UPLOAD_AWS_S3_KEY=your-key-id
FOF_UPLOAD_AWS_S3_SECRET=your-application-key
FOF_UPLOAD_AWS_S3_BUCKET=your-bucket
FOF_UPLOAD_AWS_S3_REGION=us-west-004
FOF_UPLOAD_AWS_S3_ENDPOINT=https://s3.us-west-004.backblazeb2.com

Local Storage with CDN

For local storage with a CDN in front:

FOF_UPLOAD_CDN_URL=https://cdn.example.com

Configuration Priority

Environment Variables (highest priority - when all required vars are set)
Database Settings (admin panel configuration)
Defaults (null values if neither is configured)

Mimetype regular expression

Regular expressions allow you a lot of freedom, but they are also very difficult to understand. Here are some pointers, but feel free to ask for help on the official Flarum forums, or check out regex101.com where you can interactively build and test your regex pattern.

In case you want to allow all regular file types including video, music, compressed files and images, use this:

(video\/(3gpp|mp4|mpeg|quicktime|webm))|(audio\/(aiff|midi|mpeg|mp4))|(image\/(gif|jpeg|png))|(application\/(x-(7z|rar|zip)-compressed|zip|arj|x-(bzip2|gzip|lha|stuffit|tar)|pdf))

A mimetype consists of a primary and secondary type. The primary type can be image, video and application for instance.
The secondary is like a more detailed specification, eg png, pdf etc. These two are divided by a /, in regex you have to escape this character by using: \/.

Disable or Force a particular adapter

In some circumstances, you may wish to either disable an adapter, or force the use of one. This is set in your root extend.php file.

For example, you may disable imgur

(new FoF\Upload\Extend\Adapters())
        ->disable('imgur'),

Chaining of multiple commands is also possible:

(new FoF\Upload\Extend\Adapters())
        ->disable('imgur')
        ->disable('aws-s3'),

You may also force an adapter:

(new FoF\Upload\Extend\Adapters())
        ->force('imgur'),

Adapter names currently available:

local
imgur
qiniu
aws-s3

Commands

MapFilesCommand

Using php flarum fof:upload you have a powerful tool in your hands to map uploads to posts and
clean up unused files. To do so there are two steps to take into consideration:

Mapping (--map) allows you to look through posts to identify whether which uploaded files have been used inside any posts, and store this information
Clean up (--cleanup, --cleanup-before=yyyy-mm-dd) grants you to ability to remove files that have been uploaded before the given time and haven't been mapped to any (existing) posts.

The intent of this command stems from the original concept of understand what uploads are used where and to allow removal
of unused, stale files. You can run this command manually or as a cronjob.

Example 1; only mapping files:

php flarum fof:upload --map

Example 2; map and clean up

php flarum fof:upload --map --cleanup --cleanup-before="a month ago"

Once you're happy with how the command operates, you can append the flag --force, which removes the need to confirm
the action:

php flarum fof:upload --map --cleanup --cleanup-before="last year" --force

The following (to resume) will happen when this command is put into a recurring cronjob:

based on the interval of the cronjob (daily, weekly or however)
the command will go over all uploads to discover in which posts they have been used
delete those files that have been uploaded "last year" that have not been found in posts

Testing and Security Measures

FoF Upload includes automated tests to ensure:

✅ Valid files upload successfully
✅ Restricted files are blocked
✅ SVG sanitization removes potential XSS risks

🔍 Security Tests for Malicious Files

We specifically test against:

HTML Injection (.html disguised as an image)
MIME Spoofing (e.g., .png containing a script)
Polygot Files (Files that act as two different formats)
SVG Sanitization (<script>, <foreignObject>, event handlers, external styles, etc)
ZIP & APK Handling (Ensuring APKs are valid and ZIPs are not misclassified)

Submitting Additional Test Cases

We welcome community contributes in all our extensions! Especially where security is concerned. If you find a new edge case or a file format that bypasses validation, please:

Open an issue on GitHub
Submit a test case as a PR under tests/
Describe the expected behaviour (Should the file be accepted? Should it be sanitized?)

🚀 These tests ensure FoF Upload remains secure and reliable for all Flarum users! 🚀

FAQ

AWS S3: read the AWS S3 configuration page.
Adding Templates: read the Custom Templates wiki page.
Upgrading from flagrow/upload: read the wiki article.

Links

An extension by FriendsOfFlarum