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Convert Office Docs to PDFs Automatically with Foxit PDF Services API


This content originally appeared on DEV Community and was authored by Raymond Camden

With our REST APIs, it is now possible for any developer to set up an integration and document workflow using their language of choice. But what about workflow automations? Luckily, this is even simpler (of course, depending on platform) as you can rely on the workflow service to handle a lot the heavy lifting of whatever automation needs you may have. In this blog post, I’m going to demonstrate a workflow making use of Pipedream. Pipedream is a low-code platform that lets you build flexible workflows by piecing together various small atomic steps. It’s been a favorite of mine for some time now, and I absolutely recommend it. But note that what I’ll be showing here today could absolutely be done on other platforms, like n8n.

Want the televised version? Catch the video below:

Our Office Document to PDF Workflow

Our workflow is based on Dropbox folders and handles automatic conversion of Office docs to PDFs. To support that, it does the following:

  • Listen for new files in a Dropbox folder
  • Do a quick sanity check (is it in the input subdirectory and an Office file)
  • Download the file to Pipedream
  • Send it to Foxit via the Upload API
  • Kick off the appropriate conversion based on the Office type
  • Check status via the Status API
  • When done, download the result to Pipedream
  • And finally, push it up to Dropbox in an output subdirectory

Here’s a nice graphical representation of this workflow:

Workflow chart

Before we get into the code, note that workflow platforms like Pipedream are incredibly flexible. When I build workflows with platforms like this I try to make each step as atomic, and focused as possible. I could absolutely have built a shorter, more compact version of this workflow. However, having it broken out like this makes it easier to copy and modify going forward (which is exactly how this one came about, it was based on a simpler, earlier version).

Ok, let’s break it down, step-by-step.

Getting Triggered

In Pipedream, workflows begin with a trigger. While there are many options for this, my workflow uses a “New File From Dropbox” trigger. I logged into Dropbox via Pipedream so it had access to my account. I then specified a top level folder, “Foxit”, for the integration. Additionally, there are two more important settings:

  • Recursive – this tells the trigger to file for any new file under the root directory, “Foxit”. My Dropbox Foxit folder has both an input and output directory.
  • Include Link – this tells Pipedream to ensure we get a link to the new file. This is required to download it later.

Dropbox trigger settings

Filtering the Document Flow

The next two steps are focused on filtering and stopping the workflow, if necessary. The first, end_if_output, is a built-in Pipedream step that lets me provide a condition for the workflow to end. First, I’ll check the path value from the trigger (the path of the new file) and if it contains “output”, this means it’s a new file in the output directory and the workflow should not run.

End condition

The next filter is a code step that handles two tasks. First, it checks whether the new file is a supported Office type—.docx, .xlsx, or .pptx—using our APIs. If the extension isn’t one of these, the workflow ends programmatically.

Later in the workflow, I’ll also need that same extension to route the request to the correct endpoint. So the code handles both: validation and preservation of the extension.

import os 

def handler(pd: "pipedream"):
  base, extension = os.path.splitext(pd.steps['trigger']['event']['name'])

  if extension == ".docx":
    api = "/pdf-services/api/documents/create/pdf-from-word"
  elif extension == ".xlsx":
    api = "/pdf-services/api/documents/create/pdf-from-excel"
  elif extension == ".pptx":
    api = "/pdf-services/api/documents/create/pdf-from-ppt"
  else:
    return pd.flow.exit(f"Exiting workflow due to unknow extension: {extension}.")

  return { "api":api }

As you can see, if the extension isn’t valid, I’m exiting the workflow using pd.flow.exit (while also logging out a proper message, which I can check later via the Pipedream UI). I also return the right endpoint if a supported extension was used. This will be useful later in the flow.

Download and Upload API Data

The next two steps are primarily about moving data from the input source (Dropbox) to our API (Foxit).

The first step, download_to_tmp, uses a simple Python script to transfer the Dropbox file into the /tmp directory for use in the workflow

import requests

def handler(pd: "pipedream"):
    download_url = pd.steps["trigger"]["event"]["link"]
    file_path = f"/tmp/{pd.steps['trigger']['event']['name']}"

    with requests.get(download_url, stream=True) as response:
      response.raise_for_status()
      with open(file_path, "wb") as file:
          for chunk in response.iter_content(chunk_size=8192):
            file.write(chunk)

    return file_path

Notice at the end that I return the path I used in Pipedream. This action then leads directly into the next step of uploading to Foxit via the Upload API:

import os 
import requests 

def handler(pd: "pipedream"):
  clientid = os.environ.get('FOXIT_CLIENT_ID')
  secret = os.environ.get('FOXIT_CLIENT_SECRET')
  HOST = os.environ.get('FOXIT_HOST')

  headers = {
    "client_id":clientid,
    "client_secret":secret
  }

  with open(pd.steps['download_to_tmp']['$return_value'], 'rb') as f:
    files = {'file': (pd.steps['download_to_tmp']['$return_value'], f)}

    request = requests.post(f"{HOST}/pdf-services/api/documents/upload", files=files, headers=headers)

    return request.json()

The result of this will be a documentId value that looks like so:

{
  "documentId": "<string>"
}

Pipedream lets you define environment variables and I’ve made use of them for my Foxit credentials and host. Grab your own free credentials here!

Converting the Document Using the Foxit API

The next step will actually kick off the conversion. My workflow supports three different input types (Word, PowerPoint, and Excel). These map to three API endpoints. But remember that earlier we sniffed the extension of our input and set the endpoint there. Since all three APIs work the same, that’s literally all we need to do – hit the endpoint and pass the document value from the previous step.

import os 
import requests 

def handler(pd: "pipedream"):

  clientid = os.environ.get('FOXIT_CLIENT_ID')
  secret = os.environ.get('FOXIT_CLIENT_SECRET')
  HOST = os.environ.get('FOXIT_HOST')

  headers = {
    "client_id":clientid,
    "client_secret":secret,
    "Content-Type":"application/json"
  }

  body = {
    "documentId": pd.steps['upload_to_foxit']['$return_value']['documentId']
  }

  api = pd.steps['extension_check']['$return_value']['api']

  print(f"{HOST}{api}")
  request = requests.post(f"{HOST}{api}", json=body, headers=headers)
  return request.json()

The result of this call, and nearly all of the Foxit APIs, will be a task:

{
  "taskId": "<string>"
}

Checking Your Document API Status

The next step is one that may take a few seconds – checking the job status. Foxit’s endpoint returns a value like so:

{
  "taskId": "<string>",
  "status": "<string>",
  "progress": "<int32>",
  "resultDocumentId": "<string>",
  "error": {
    "code": "<string>",
    "message": "<string>"
  }
}

To use this, I just hit the API, check for status, and if it’s not done, wait five seconds and call it again. Here’s the Python code for this:

import os 
import requests 
from time import sleep 

def handler(pd: "pipedream"):

  clientid = os.environ.get('FOXIT_CLIENT_ID')
  secret = os.environ.get('FOXIT_CLIENT_SECRET')
  HOST = os.environ.get('FOXIT_HOST')

  headers = {
    "client_id":clientid,
    "client_secret":secret,
    "Content-Type":"application/json"
  }

  done = False
  while done is False:

    request = requests.get(f"{HOST}/pdf-services/api/tasks/{pd.steps['create_conversion_job']['$return_value']['taskId']}", headers=headers)
    status = request.json()
    if status["status"] == "COMPLETED":
      done = True
      return status
    elif status["status"] == "FAILED":
      print("Failure. Here is the last status:")
      print(status)
      return pd.flow.exit("Failure in job")
    else:
      print(f"Current status, {status['status']}, percentage: {status['progress']}")
      sleep(5)

As shown, errors are simply logged by default—but you could enhance this by adding notifications, such as emailing an admin, sending a text message, or other alerts.

On success, the final output is passed along, including the key value we care about: resultDocumentId.

Download and Upload – Again

Ok, if the workflow has gotten this far, it’s time to finish the process. The next step handles downloading the result from Foxit using the download endpoint:

import requests
import os

def handler(pd: "pipedream"):
  clientid = os.environ.get('FOXIT_CLIENT_ID')
  secret = os.environ.get('FOXIT_CLIENT_SECRET')
  HOST = os.environ.get('FOXIT_HOST')

  headers = {
    "client_id":clientid,
    "client_secret":secret,
  }

  # Given a file of input.docx, we need to use input.pdf
  base_name, _ = os.path.splitext(pd.steps['trigger']['event']['name'])
  path = f"/tmp/{base_name}.pdf"
  print(path) 

  with open(path, "wb") as output:

    bits = requests.get(f"{HOST}/pdf-services/api/documents/{pd.steps['check_job']['$return_value']['resultDocumentId']}/download", stream=True, headers=headers).content 
    output.write(bits)

    return {
      "filename":f"{base_name}.pdf",
      "path":path
    }

Note that I’m using the base name of the input, which is basically the filename minus the extension. So for example, input.docx will become input, which I then slap a pdf extension on to create the filename used to store locally to Pipedream.

Finally, I push the file back up to Dropbox, but for this, I can use a built-in Pipedream step that can upload to Dropbox. Here’s how I configured it:

  • Path: Once again, Foxit
  • File Name: This one’s a bit more complex, I want to store the value in the output subdirectory, and ensure the filename is dynamic. Pipedream lets you mix and match hard-coded values and expressions. I used this to enable that: output/{{steps.download_result_to_tmp.$return_value.filename}}. In this expression the portion inside the double bracket will be dynamic based on the PDF file generated previously.
  • File Path: This is an expression as well, pointing to where I saved the file previously: {{steps.download_result_to_tmp.$return_value.path}}
  • Mode: Finally, the mode attribute specifies what to do on a conflict. This setting will be based on whatever your particular workflow needs are, but for my workflow, I simply told Dropbox to overwrite the existing file.

Here’s how that step looks configured in Pipedream:

Upload to Dropbox step

Conclusion

Believe it or not, that’s the entire workflow. Once enabled, it runs in the back ground and I can simply place any files into my Dropbox folder and my Office docs will be automatically converted. What’s next? Definitely get your own free credentials and check out the docs to get started. If you run into any trouble at all, hit is up on the forums and we’ll be glad to help!


This content originally appeared on DEV Community and was authored by Raymond Camden