og:image, preproccesses, first image and you

[joelouthan]

ChatGPT: Handlebars og:image Setter

[joelouthan]

Askeed at rust-lang/mdbook: rust-lang/mdBook#1416 (comment)

[joelouthan]

Refer to ChatGPT: Image Loading Issues

[joelouthan]

Create a new Rust project

You can create a new Rust project using cargo, the Rust package manager:

arduino

cargo new my_preprocessor

This command will create a new directory my_preprocessor with a basic Rust project structure.

1. Add dependencies

Add mdbook as a dependency in your Cargo.toml:

[dependencies]
mdbook = "0.4.12"  # Use the version of mdbook you're working with

2. Implement the Preprocessor trait

You will need to create a struct (let's call it MyPreprocessor) that implements the Preprocessor trait from the mdbook crate. Here's a skeleton of what that might look like:

use mdbook::preprocess::{Preprocessor, PreprocessorContext, CmdPreprocessor};
use mdbook::book::{Book, BookItem};
use mdbook::errors::Result;

pub struct MyPreprocessor;

impl Preprocessor for MyPreprocessor {
    fn name(&self) -> &str {
        "my_preprocessor"
    }

    fn run(&self, _ctx: &PreprocessorContext, mut book: Book) -> Result<Book> {
        // This is where you would modify the book.
        // As a simple example, this preprocessor will add a message to the start of every chapter.

        book.for_each_mut(|section: &mut BookItem| {
            if let BookItem::Chapter(chapter) = section {
                let new_content = format!("<!-- Processed by MyPreprocessor -->\n{}", chapter.content);
                chapter.content = new_content;
            }
        });

        Ok(book)
    }

    fn supports_renderer(&self, renderer: &str) -> bool {
        renderer != "not-supported-renderer"
    }
}

In the run method, you iterate over each section of the book. If the section is a chapter, you prepend a message to the content.

3. Create a main function to interface with mdbook

You also need a main function that mdbook can call. You can use the CmdPreprocessor struct from the mdbook crate to handle most of the details:

fn main() -> Result<()> {
    let (ctx, book) = CmdPreprocessor::parse_input(std::io::stdin())?;

    let preprocessor = MyPreprocessor;
    let processed_book = preprocessor.run(&ctx, book)?;

    serde_json::to_writer(std::io::stdout(), &processed_book)?;

    Ok(())
}

4. Build your preprocessor

Use cargo build --release to build your preprocessor. The resulting binary will be in the target/release directory.

5. Add your preprocessor to your book

In your book.toml, you can add your preprocessor to the preprocessor field:

[preprocessor.my_preprocessor]
command = "path/to/your/preprocessor/binary"

[joelouthan]

ugh closed for now