🛠 Script Syntax and Parameter Substitution

When defining a CCP method, you provide two shell-based scripts:

deploy-script: sets up the environment (e.g. installs dependencies, downloads files)
execute-script: runs your algorithm using the inputs provided

These scripts support dynamic variable injection and conditional logic.

📌 Placeholder Syntax: `{{parameter_id}}`

Any input parameter defined in your method.json can be referenced in scripts using double curly braces.

echo "The input URL is {{file_url}}"

At runtime, CCP will substitute {{file_url}} with the actual value passed by the user.

📥 Downloading Files with `curl`

Use curl to download files passed as remote URLs:

curl -L {{file_url}} -o /ccp_data/input.txt

Notes:

-L follows redirects (important for Google Drive, Dropbox, etc.)
Save everything in /ccp_data/ to make outputs accessible

⚠️ Optional Parameters

Use shell logic to check if a parameter has been set before using it:

[ -n "{{optional_param}}" ] && echo "Optional param was provided"

Example

[ -n "{{mask_url}}" ] && curl -L {{mask_url}} -o /ccp_data/mask.png

This prevents the script from failing when the user leaves a field empty.

🔁 Building Dynamic Commands

For complex CLI tools, build your command step-by-step:

cmd="wordcloud_cli --text /ccp_data/input.txt"
cmd="$cmd --width {{width}} --height {{height}}"
[ -n "{{max_words}}" ] && cmd="$cmd --max_words {{max_words}}"
eval $cmd

This allows you to include optional flags only when they are present.

📦 Output Location

Always write result files to /ccp_data/, like:

python tool.py --output /ccp_data/results.csv

CCP will include these in the downloadable archive and display them in the UI.

✅ Quick Reference

Task	Example
Inject parameter	`{{input}}`
Required download	`curl -L {{url}} -o /ccp_data/file.txt`
Optional download	`[ -n "{{url}}" ] && curl ...`
Dynamic command	`cmd="..."; eval $cmd`
Output file	Write to `/ccp_data/`