monolith/src/utils.rs

use reqwest::blocking::Client;
use reqwest::header::CONTENT_TYPE;
use std::collections::HashMap;
use std::fs;
use std::path::Path;

use crate::url::{clean_url, data_url_to_data, file_url_to_fs_path, is_data_url, is_file_url};

const MAGIC: [[&[u8]; 2]; 18] = [
    // Image
    [b"GIF87a", b"image/gif"],
    [b"GIF89a", b"image/gif"],
    [b"\xFF\xD8\xFF", b"image/jpeg"],
    [b"\x89PNG\x0D\x0A\x1A\x0A", b"image/png"],
    [b"<svg ", b"image/svg+xml"],
    [b"RIFF....WEBPVP8 ", b"image/webp"],
    [b"\x00\x00\x01\x00", b"image/x-icon"],
    // Audio
    [b"ID3", b"audio/mpeg"],
    [b"\xFF\x0E", b"audio/mpeg"],
    [b"\xFF\x0F", b"audio/mpeg"],
    [b"OggS", b"audio/ogg"],
    [b"RIFF....WAVEfmt ", b"audio/wav"],
    [b"fLaC", b"audio/x-flac"],
    // Video
    [b"RIFF....AVI LIST", b"video/avi"],
    [b"....ftyp", b"video/mp4"],
    [b"\x00\x00\x01\x0B", b"video/mpeg"],
    [b"....moov", b"video/quicktime"],
    [b"\x1A\x45\xDF\xA3", b"video/webm"],
];

const PLAINTEXT_MEDIA_TYPES: &[&str] = &[
    "image/svg+xml",
    "text/css",
    "text/html",
    "text/javascript",
    "text/plain",
];

pub fn detect_media_type(data: &[u8], url: &str) -> String {
    for item in MAGIC.iter() {
        if data.starts_with(item[0]) {
            return String::from_utf8(item[1].to_vec()).unwrap();
        }
    }

    if url.to_lowercase().ends_with(".svg") {
        return str!("image/svg+xml");
    }

    str!()
}

pub fn is_plaintext_media_type(media_type: &str) -> bool {
    PLAINTEXT_MEDIA_TYPES.contains(&media_type.to_lowercase().as_str())
}

pub fn retrieve_asset(
    cache: &mut HashMap<String, Vec<u8>>,
    client: &Client,
    parent_url: &str,
    url: &str,
    opt_silent: bool,
) -> Result<(Vec<u8>, String, String), reqwest::Error> {
    if url.len() == 0 {
        // Provoke error
        client.get("").send()?;
    }

    if is_data_url(&url) {
        let (media_type, data) = data_url_to_data(url);
        Ok((data, url.to_string(), media_type))
    } else if is_file_url(&url) {
        // Check if parent_url is also file:///
        // (if not, then we don't embed the asset)
        if !is_file_url(&parent_url) {
            // Provoke error
            client.get("").send()?;
        }

        let fs_file_path: String = file_url_to_fs_path(url);
        let path = Path::new(&fs_file_path);
        if path.exists() {
            if !opt_silent {
                eprintln!("{}", &url);
            }

            Ok((fs::read(&fs_file_path).expect(""), url.to_string(), str!()))
        } else {
            // Provoke error
            Err(client.get("").send().unwrap_err())
        }
    } else {
        let cache_key: String = clean_url(&url);

        if cache.contains_key(&cache_key) {
            // URL is in cache, we get and return it
            if !opt_silent {
                eprintln!("{} (from cache)", &url);
            }

            Ok((
                cache.get(&cache_key).unwrap().to_vec(),
                url.to_string(),
                str!(),
            ))
        } else {
            // URL not in cache, we retrieve the file
            let mut response = client.get(url).send()?;
            let res_url = response.url().to_string();

            if !opt_silent {
                if url == res_url {
                    eprintln!("{}", &url);
                } else {
                    eprintln!("{} -> {}", &url, &res_url);
                }
            }

            let new_cache_key: String = clean_url(&res_url);

            // Convert response into a byte array
            let mut data: Vec<u8> = vec![];
            response.copy_to(&mut data)?;

            // Attempt to obtain media type by reading the Content-Type header
            let media_type = response
                .headers()
                .get(CONTENT_TYPE)
                .and_then(|header| header.to_str().ok())
                .unwrap_or("");

            // Add to cache
            cache.insert(new_cache_key, data.clone());

            Ok((data, res_url, media_type.to_string()))
        }
    }
}