Process images in content metadata #99

patrickfournier · 2025-11-12T14:27:41Z

This pull request adds support for processing image paths found in metadata fields (such as og_image) in addition to images in HTML content. It introduces a new configuration option to specify which metadata fields should be processed and which transformations to apply. The implementation includes the new processing logic, updates to the documentation, and corresponding tests.

New feature: Process images in metadata fields

Added the ability to process images referenced in metadata fields by introducing the IMAGE_PROCESS_METADATA setting. This allows users to specify which metadata fields should be processed and which image transformation to apply. The processing supports per-instance overrides and saves original metadata values for reference. (README.md, pelican/plugins/image_process/image_process.py) [1] [2]

Documentation updates

Updated the documentation to explain how to use the new IMAGE_PROCESS_METADATA setting, including examples and override mechanisms. (README.md) [1] [2]

Testing

Added parameterized tests for the new metadata processing logic, covering default behavior, transformation application, and per-instance overrides. (pelican/plugins/image_process/test_image_process.py)

Copilot

Pull Request Overview

This pull request introduces metadata image processing functionality to the Image Process plugin, allowing users to process images referenced in metadata fields (such as og_image) in addition to images in HTML content. The implementation adds a new configuration setting, updates documentation, and includes comprehensive tests.

Adds IMAGE_PROCESS_METADATA setting to specify which metadata fields should be processed and which transformations to apply
Supports per-instance transformation overrides using {transform-name} prefix syntax
Refactors compute_paths function to accept image URL strings instead of dictionary objects

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.

File	Description
pelican/plugins/image_process/image_process.py	Implements metadata processing logic with the new `process_metadata` function, refactors `compute_paths` signature to accept strings, and registers the new signal handler
pelican/plugins/image_process/test_image_process.py	Adds parameterized tests for metadata processing covering default behavior, transformation application, and override mechanisms; updates tests to use refactored `compute_paths` signature
README.md	Documents the new metadata processing feature with usage examples and configuration details

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

README.md

pelican/plugins/image_process/test_image_process.py

pelican/plugins/image_process/image_process.py

README.md

pelican/plugins/image_process/image_process.py

In Python 3.14, `urllib.parse.urljoin` handles `//` differently than in previous versions.

justinmayer

I made a small suggestion for the README, but otherwise this looks good to me. Any thoughts, @minchinweb?

README.md

minchinweb

A couple thoughts on how to make the documentation a little clearer. The plugin is hugely powerful, but annoying complex to get set up from scratch, so the easier we can make that, they better.

And a request to guard against reusing "special" "keys", already is use elsewhere.

minchinweb · 2025-11-14T02:20:18Z

README.md

+IMAGE_PROCESS_METADATA = {
+    "og_image": "og-image-transform",
+}
+```


Could you provide an example IMAGE_PROCESS here, showing the listed transformation (maybe scale to the proper dimensions??)?

minchinweb · 2025-11-14T02:21:16Z

README.md

+It is possible to override the transformation applied to a specific instance of a metadata field by prefixing
+the metadata value with `{transform-name}`. For example, if you have defined
+`IMAGE_PROCESS_METADATA` as above, you can override the transformation for a specific article
+by setting its `og_image` metadata value to `{other-transform}/path/to/image.jpg`.


Can you add a (simple) sample file (i.e. a Markdown post) showing this in the metadata of the post in the actual format?

minchinweb · 2025-11-14T02:22:41Z

README.md

+metadata field names to transformation names. For example:
+
+```python
+IMAGE_PROCESS_METADATA = {


Add a comment here noting this the the pelicanconf.py file. E.g.

# pelicanconf.py IMAGE_PROCESS_METADATA = { # ...the rest

minchinweb · 2025-11-14T02:27:17Z

pelican/plugins/image_process/image_process.py

+        if isinstance(value, str) and key in metadata_to_process:
+            derivative = generator.context["IMAGE_PROCESS_METADATA"][key]
+            # If value starts with {some-other-derivative}, override derivative
+            if value.startswith("{") and "}" in value:


I think we should we add a guard against using "keys" such as {attach} or {static} that have special meaning already to Pelican. I think the list can be imported from pelican, which would be ideal rather than maintaining such a list here manually.

Probably best to throw a warning if one of the disallowed keys is encountered.

I did not realize that I was using the same syntax as the {static} and {attach} feature. I think I should use a different syntax to avoid conflicts. I could use [transform-name] instead. What do you think?

It's hard to find something that isn't in use somewhere... for example, the [] reminds me of (the first half of) a Markdown link, and I also worry that it might get interpreted as a list if someone is trying to process the post metadata as YAML.

I think the {} is okay, as it already feels "Pelican-y" (exactly because it is used elsewhere). One option would be to "namespace" it; i.e. require that all keys start with the "image-process" namespace. E.g. {image-process-transform-name}. The trade-off is it gets kind of verbose.

Or just blacklist the keys that Pelican is already using.

I think the list can be imported from pelican,

I went looking for this list tonight and can't find it :(

I added a check in the code and a test case.

minchinweb · 2025-11-14T02:29:32Z

Also, which is prefer? For me to make suggestions like this for documentation, or just write it myself and push it to the PR and ask for your review?

patrickfournier · 2025-11-14T05:18:18Z

@minchinweb Thanks for the comments. Unless it is something very minor, I prefer suggestions than additional commits, because we can discuss them (if there is a need for discussion) and I feel it is less work for the reviewer (no need to setup a dev environment, no need to test the suggestions, no need to lint the files, ...).

- Clarify the feature documentation in README.md. - Ignore Pelican special linking directives. - Add a test for Pelican special linking directives.

minchinweb

Thanks for all your work on this!

justinmayer

Many thanks to @patrickfournier for the significant enhancement and to @minchinweb for reviewing! 🏅

patrickfournier added 5 commits November 11, 2025 14:41

Add metadata processing for image URLs.

48b312c

Save original values.

3dcf90f

Make sure the image URL is absolute.

e9773df

Update doc

c5b9ca2

Fix format and test.

824407b

patrickfournier requested a review from Copilot November 12, 2025 14:40

Copilot started reviewing on behalf of patrickfournier November 12, 2025 14:41 View session

Copilot finished reviewing on behalf of patrickfournier November 12, 2025 14:44

Copilot AI reviewed Nov 12, 2025

View reviewed changes

patrickfournier added 3 commits November 12, 2025 23:47

Avoid using exotic // as SITEURL.

1a6a75a

In Python 3.14, `urllib.parse.urljoin` handles `//` differently than in previous versions.

Test that original metadata is preserved.

1e0a0c8

Apply Copilot suggestions

8421835

patrickfournier marked this pull request as ready for review November 13, 2025 05:20

patrickfournier requested review from justinmayer and minchinweb November 13, 2025 05:21

justinmayer reviewed Nov 13, 2025

View reviewed changes

README.md Outdated Show resolved Hide resolved

Apply @justinmayer review suggestion.

0ded056

minchinweb requested changes Nov 14, 2025

View reviewed changes

Apply review suggestions from @minchinweb.

dc4ec42

- Clarify the feature documentation in README.md. - Ignore Pelican special linking directives. - Add a test for Pelican special linking directives.

patrickfournier requested a review from minchinweb November 17, 2025 20:01

minchinweb approved these changes Nov 17, 2025

View reviewed changes

justinmayer changed the title ~~Process metadata~~ Process images in content metadata Nov 18, 2025

Prepare release

81fd081

justinmayer approved these changes Nov 18, 2025

View reviewed changes

justinmayer merged commit 29bafa9 into pelican-plugins:main Nov 18, 2025
12 checks passed

Uh oh!

Process images in content metadata #99

Process images in content metadata #99

Uh oh!

Conversation

patrickfournier commented Nov 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Reviewed Changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

justinmayer left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

minchinweb left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

patrickfournier Nov 17, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

minchinweb commented Nov 14, 2025

Uh oh!

patrickfournier commented Nov 14, 2025

Uh oh!

minchinweb left a comment

Choose a reason for hiding this comment

Uh oh!

justinmayer left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

patrickfournier commented Nov 12, 2025 •

edited

Loading

patrickfournier Nov 17, 2025 •

edited

Loading