Export files to Amazon S3

🤖/s3/store exports encoding results to Amazon S3.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "UploadAndAbortWithinPrefix",
      "Effect": "Allow",
      "Action": ["s3:PutObject", "s3:AbortMultipartUpload"],
      "Resource": "arn:aws:s3:::{BUCKET_NAME}/uploads/*"
    }
  ]
}

Usage example

{
  "steps": {
    "exported": {
      "credentials": "YOUR_AWS_CREDENTIALS",
      "path": "my_target_folder/${unique_prefix}/${file.url_name}",
      "robot": "/s3/store",
      "use": ":original"
    }
  }
}

Parameters

• interpolate

  boolean | Record<string, boolean>

  Controls whether Assembly Variables are interpolated for individual instruction fields.

  By default, most Robot instruction fields interpolate Assembly Variables. Set this to false to treat every instruction field as literal text, or set an individual field path to false to treat only that field as literal text. For Robot-specific fields that are literal by default, set this to true or set that field path to true to opt back into interpolation.

  Use field names such as path, or dotted paths such as ffmpeg.vf for nested objects.

• output_meta

  Record<string, boolean> | boolean | Array<string>

  Allows you to specify a set of metadata that is more expensive on CPU power to calculate, and thus is disabled by default to keep your Assemblies processing fast.

  For images, you can add "has_transparency": true in this object to extract if the image contains transparent parts and "dominant_colors": true to extract an array of hexadecimal color codes from the image.

  For images, you can also add "blurhash": true to extract a BlurHash⁠ string — a compact representation of a placeholder for the image, useful for showing a blurred preview while the full image loads.

  For images, "thumbhash": true instead extracts a base64-encoded ThumbHash⁠ into meta.thumbhash, together with meta.has_alpha (whether an alpha channel exists, even when fully opaque). It describes EXIF-oriented pixels and uses the first frame of animated images. Extraction is best-effort: images above 40 megapixels, unsupported formats, or a failed/bounded decode produce no placeholder. Successful extraction adds a metadata charge equivalent to 20% of that file's bytes. No ThumbHash surcharge applies when disabled or when no hash is produced.

  Set this option on the Step producing the image, such as /upload/handle for uploaded originals or /image/resize for processed outputs. Setting it only on /transloadit/store does not request extraction: storage preserves the producer's metadata. Transloadit Storage persists a generated hash with its immutable version and returns it in stored results and native asset reads. Direct S3 uploads do not generate placeholders. A placeholder contains image information, so protect it with the same access controls as the full image.

  For videos, you can add the "colorspace": true parameter to extract the colorspace of the output video.

  For videos, you can also add "interlaced": true to detect whether the video is interlaced. This combines the cheap ffprobe field_order flag with a bounded idet sampling pass over the first frames of the source, exposing interlaced, field_order, and a diagnostic interlace_detection object under file.meta. This is computationally expensive and billed accordingly.

  For audio, you can add "mean_volume": true to get a single value representing the mean average volume of the audio file.

  You can also set this to false to skip metadata extraction and speed up transcoding.

• user_meta

  Record<string, any>(default: {})

  Adds custom JSON metadata to each emitted file without changing its contents. Nested objects and arrays are supported.

  Inheritance depends on the Robot. Values merge with existing user_meta on the output file; the current Step replaces matching top-level keys. Assign required keys explicitly when a Robot creates fresh outputs.

  In processing Steps, ${file.*} refers to the first input and ${result.*} to the emitted file. Values are evaluated per output after the Robot runs, before subsequent metadata extraction and temporary storage. On :original, values are evaluated per upload before metadata extraction.

  Downstream Steps read ${file.user_meta.key}. See Custom metadata for a complete example and inheritance rules.

• result

  boolean(default: false)

  Whether the results of this Step should be present in the Assembly Status JSON

• queue

  batch

  Setting the queue to 'batch', manually downgrades the priority of jobs for this step to avoid consuming Priority job slots for jobs that don't need zero queue waiting times

• force_accept

  boolean(default: false)

  Force a Robot to accept a file type it would have ignored.

  By default, Robots ignore files they are not familiar with. 🤖/video/encode, for example, will happily ignore input images.

  With the force_accept parameter set to true, you can force Robots to accept all files thrown at them. This will typically lead to errors and should only be used for debugging or combatting edge cases.

• ignore_errors

  boolean | Array<meta | execute>(default: [])

  Ignore errors during specific phases of processing.

  Setting this to ["meta"] will cause the Robot to ignore errors during metadata extraction.

  Setting this to ["execute"] will cause the Robot to ignore errors during the main execution phase.

  Setting this to true is equivalent to ["meta", "execute"] and will ignore errors in both phases.

• use

  string | Array<string> | Array<object> | object

  Specifies which Step(s) to use as input.

  • You can pick any names for Steps except ":original" (reserved for user uploads handled by Transloadit)
  • You can provide several Steps as input with arrays:

    {
      "use": [
        ":original",
        "encoded",
        "resized"
      ]
    }
    

  • You can also tag input Steps with as to pass semantic intent to robots:

    {
      "use": [
        {
          "name": ":original",
          "as": "image"
        },
        {
          "name": ":original",
          "as": "mask"
        }
      ]
    }
    

  Tip

  That's likely all you need to know about use, but you can view Advanced use cases.

• credentials

  string

  Please create your associated Template Credentials in your Transloadit account and use the name of your Template Credentials as this parameter's value. They will contain the values for your S3 bucket, key, secret and bucket_region.

  While we recommend to use Template Credentials at all times, some use cases demand dynamic credentials for which using Template Credentials is too unwieldy because of their static nature. If you have this requirement, feel free to use the following parameters instead: "bucket", "bucket_region" (for example: "us-east-1" or "eu-west-2"), "key", "secret".

• path

  string(default: "${unique_prefix}/${file.url_name}")

  The path at which the file is to be stored. This may include any available Assembly variables. The path must not be a directory.

• url_prefix

  string(default: "http://{bucket}.s3.amazonaws.com/")

  The URL prefix used for the returned URL, such as "http://my.cdn.com/some/path/".

• acl

  bucket-default | private | public | public-read(default: "public-read")

  The ACL used for this file. The default remains "public-read", which can conflict with S3 Block Public Access and disabled ACLs. For modern private buckets, explicitly set "bucket-default" to omit the generated ACL header, and do not supply ACL/grant headers in headers. "private" still sends an ACL.

• check_integrity

  boolean(default: false)

  Calculate and submit the file's checksum in order for S3 to verify its integrity after uploading, which can help with occasional file corruption issues.

  Enabling this option adds to the overall execution time, as integrity checking can be CPU intensive, especially for larger files.

• headers

  Record<string, string>(default: {"Content-Type":"${file.mime}"})

  An object containing a list of headers to be set for this file on S3, such as { FileURL: "${file.url_name}" }. This can also include any available Assembly Variables. You can find a list of available headers here⁠.

  Object Metadata can be specified using x-amz-meta-* headers. Note that these headers do not support non-ASCII metadata values⁠.

• tags

  Record<string, string>(default: {})

  Object tagging allows you to categorize storage. You can associate up to 10 tags with an object. Tags that are associated with an object must have unique tag keys.

• host

  string(default: "s3.amazonaws.com")

  The host of the storage service used. This only needs to be set when the storage service used is not Amazon S3, but has a compatible API (such as hosteurope.de). The default protocol used is HTTP, for anything else the protocol needs to be explicitly specified. For example, prefix the host with https:// or s3:// to use either respective protocol.

• no_vhost

  boolean(default: false)

  Set to true if you use a custom host and run into access denied errors.

• sign_urls_for

  string | number

  This parameter provides signed URLs in the result JSON (in the signed_url and signed_ssl_url properties). The number that you set this parameter to is the URL expiry time in seconds. If this parameter is not used, no URL signing is done.

• session_token

  string

  The session token belonging to the temporary AWS access key ID and secret access key supplied for this upload. The Robot does not assume a role or refresh these credentials; they must remain valid for the upload.

Demos

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