Import files from web servers

The result of this Robot will carry a field import_url in their metadata, which references the URL from which they were imported. Further conversion results that use this file will also carry this import_url field. This allows you to to match conversion results with the original import URL that you used.

This Robot knows to interpret links to files on these services:

• Dropbox
• Google Drive
• Google Docs
• OneDrive

Instead of downloading the HTML page previewing the file, the actual file itself will be imported.

Parameters

• use

  String / Array of Strings / Object required

  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"
    ]
    

  💡 That’s likely all you need to know about use, but you can view advanced use cases:

  › Advanced use cases

  • Step bundling. Some Robots can gather several Step results for a single invocation. For example, the /file/compress Robot would normally create one archive for each file passed to it. If you'd set bundle_steps to true, however, it will create one archive containing all the result files from all Steps you give it. To enable bundling, provide an object like the one below to the use parameter:

    "use": {
      "steps": [
        ":original",
        "encoded",
        "resized"
      ],
      "bundle_steps": true
    }
    

    This is also a crucial parameter for the /video/adaptive Robot, otherwise you'll generate 1 playlist for each viewing quality.
    Keep in mind that all input Steps must be present in your Template. If one of them is missing (for instance it is rejected by a filter), no result is generated because the Robot waits indefinitely for all input Steps to be finished.

    Here’s a demo that showcases Step bundling.

  • Group by original. Sticking with the /file/compress Robot example, you can set group_by_original to true, in order to create a separate archive for each of your uploaded or imported files, instead of creating one archive containing all originals (or one per resulting file). This is important for for the /media/playlist Robot where you'd typically set:

    "use": {
      "steps": [
        "segmented"
      ],
      "bundle_steps": true,
      "group_by_original": true
    }
    

  • Fields. You can be more discriminatory by only using files that match a field name by setting the fields property. When this array is specified, the corresponding Step will only be executed for files submitted through one of the given field names, which correspond with the strings in the name attribute of the HTML file input field tag for instance. When using a back-end SDK, it corresponds with myFieldName1 in e.g.: $transloadit->addFile('myFieldName1', './chameleon.jpg').

    This parameter is set to true by default, meaning all fields are accepted.

    Example:

    "use": {
      "steps": [ ":original" ],
      "fields": [ "myFieldName1" ]
    }
    

  • Use as. Sometimes Robots take several inputs. For instance, the /video/merge Robot can create a slideshow from audio and images. You can map different Steps to the appropriate inputs.

    Example:

    "use": {
      "steps": [
        { "name": "audio_encoded", "as": "audio" },
        { "name": "images_resized", "as": "image" }
      ]
    }
    

    Sometimes the ordering is important, for instance, with our concat Robots. In these cases, you can add an index that starts at 1. You can also optionally filter by the multipart field name. Like in this example, where all files are coming from the same source (end-user uploads), but with different <input> names:

    Example:

    "use": {
      "steps": [
        { "name": ":original", "fields": "myFirstVideo", "as": "video_1" },
        { "name": ":original", "fields": "mySecondVideo", "as": "video_2" },
        { "name": ":original", "fields": "myThirdVideo", "as": "video_3" }
      ]
    }
    

    For times when it is not apparent where we should put the file, you can use Assembly Variables to be specific. For instance, you may want to pass a text file to the /image/resize Robot to burn the text in an image, but you are burning multiple texts, so where do we put the text file? We specify it via ${use.text_1}, to indicate the first text file that was passed.

    Example:

    "watermarked": {
      "robot": "/image/resize",
      "use"  : {
        "steps": [
          { "name": "resized", "as": "base" },
          { "name": "transcribed", "as": "text" },
        ],
      },
      "text": [
        {
          "text"  : "Hi there",
          "valign": "top",
          "align" : "left",
        },
        {
          "text"    : "From the 'transcribed' Step: ${use.text_1}",
          "valign"  : "bottom",
          "align"   : "right",
          "x_offset": 16,
          "y_offset": -10,
        }
      ]
    }
    

• url

  String / Array of Strings required

  The URL from which the file to be imported can be retrieved.

  You can also specify an array of URLs or a string of | delimited URLs to import several files at once. Please also check the url_delimiter parameter for that.

• url_delimiter

  String ⋅ default: "|"

  Provides the delimiter that is used to split the URLs in your url parameter value.

• headers

  Array of Strings ⋅ default: []

  Custom headers to be sent for file import.

  This is an empty array by default, such that no additional headers except the necessary ones (e.g. Host) are sent.

• force_name

  String / Array of Strings / Null ⋅ default: null

  Custom name for the imported file(s). Defaults to null, which means the file names are derived from the supplied URL(s).

• ignore_errors

  Array of Strings / Boolean ⋅ default: []

  Possible array members are "meta" and "import".

  You might see an error when trying to extract metadata from your imported files. This happens, for example, for files with a size of zero bytes. Including "meta" in the array will cause the Robot to not stop the import (and the entire Assembly) when that happens.

  Including "import" in the array will ensure the Robot does not cease to function on any import errors either.

  To keep backwards compatibility, setting this parameter to true will set it to ["meta", "import"] internally.

• fail_fast

  Boolean ⋅ default: false

  Disable the internal retry mechanism, and fail immediately if a resource can't be imported. This can be useful for performance critical applications.

Demos

• Add an empty audio track to still video
• Add watermark to a song
• Concatenate two audio files
• Concatenate video files
• Encode a fade effect between concatenated video files.
• Fade effect between concatenated audio tracks
• Generate a slideshow from a series of images
• Generate a video from an image sequence
• Insert an ad into a video at a specific time
• Insert cover art into an audio file
• Merge an audio and a video file
• Merge an audio file and an image to generate a video

Related blog posts

• Fast failing for the /http/import Robot June 1, 2021
• Convert Markdown to HTML (and PDF) April 19, 2021
• Two Small Feature Updates February 11, 2012
• Adding Support for Audio Encoding November 21, 2011