337 lines
9.6 KiB
Rust
337 lines
9.6 KiB
Rust
use crate::{settings::structs::Settings, version::VERSION, LemmyError, REQWEST_TIMEOUT};
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use anyhow::anyhow;
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use encoding::{all::encodings, DecoderTrap};
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use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
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use reqwest_middleware::ClientWithMiddleware;
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use serde::{Deserialize, Serialize};
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use std::future::Future;
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use thiserror::Error;
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use tracing::{error, info};
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use url::Url;
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use webpage::HTML;
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#[derive(Clone, Debug, Error)]
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#[error("Error sending request, {0}")]
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struct SendError(pub String);
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#[derive(Clone, Debug, Error)]
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#[error("Error receiving response, {0}")]
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pub struct RecvError(pub String);
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#[tracing::instrument(skip_all)]
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pub async fn retry<F, Fut, T>(f: F) -> Result<T, reqwest_middleware::Error>
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where
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F: Fn() -> Fut,
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Fut: Future<Output = Result<T, reqwest_middleware::Error>>,
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{
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retry_custom(|| async { Ok((f)().await) }).await
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}
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#[tracing::instrument(skip_all)]
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async fn retry_custom<F, Fut, T>(f: F) -> Result<T, reqwest_middleware::Error>
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where
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F: Fn() -> Fut,
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Fut: Future<Output = Result<Result<T, reqwest_middleware::Error>, reqwest_middleware::Error>>,
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{
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let mut response: Option<Result<T, reqwest_middleware::Error>> = None;
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for _ in 0u8..3 {
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match (f)().await? {
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Ok(t) => return Ok(t),
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Err(reqwest_middleware::Error::Reqwest(e)) => {
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if e.is_timeout() {
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response = Some(Err(reqwest_middleware::Error::Reqwest(e)));
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continue;
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}
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return Err(reqwest_middleware::Error::Reqwest(e));
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}
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Err(otherwise) => {
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return Err(otherwise);
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}
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}
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}
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response.expect("retry http request")
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}
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#[derive(Deserialize, Serialize, Debug, PartialEq, Clone)]
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pub struct SiteMetadata {
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pub title: Option<String>,
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pub description: Option<String>,
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image: Option<Url>,
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pub html: Option<String>,
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}
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/// Fetches the post link html tags (like title, description, image, etc)
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#[tracing::instrument(skip_all)]
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pub async fn fetch_site_metadata(
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client: &ClientWithMiddleware,
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url: &Url,
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) -> Result<SiteMetadata, LemmyError> {
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info!("Fetching site metadata for url: {}", url);
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let response = client
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.get(url.as_str())
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.timeout(REQWEST_TIMEOUT)
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.send()
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.await?;
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// Can't use .text() here, because it only checks the content header, not the actual bytes
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// https://github.com/LemmyNet/lemmy/issues/1964
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let html_bytes = response
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.bytes()
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.await
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.map_err(|e| RecvError(e.to_string()))?
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.to_vec();
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let tags = html_to_site_metadata(&html_bytes)?;
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Ok(tags)
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}
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fn html_to_site_metadata(html_bytes: &[u8]) -> Result<SiteMetadata, LemmyError> {
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let html = String::from_utf8_lossy(html_bytes);
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// Make sure the first line is doctype html
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let first_line = html
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.trim_start()
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.lines()
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.into_iter()
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.next()
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.ok_or_else(|| LemmyError::from_message("No lines in html"))?
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.to_lowercase();
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if !first_line.starts_with("<!doctype html>") {
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return Err(LemmyError::from_message(
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"Site metadata page fetch is not DOCTYPE html",
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));
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}
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let mut page = HTML::from_string(html.to_string(), None)?;
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// If the web page specifies that it isn't actually UTF-8, re-decode the received bytes with the
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// proper encoding. If the specified encoding cannot be found, fall back to the original UTF-8
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// version.
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if let Some(charset) = page.meta.get("charset") {
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if charset.to_lowercase() != "utf-8" {
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if let Some(encoding_ref) = encodings().iter().find(|e| e.name() == charset) {
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if let Ok(html_with_encoding) = encoding_ref.decode(html_bytes, DecoderTrap::Replace) {
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page = HTML::from_string(html_with_encoding, None)?;
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}
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}
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}
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}
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let page_title = page.title;
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let page_description = page.description;
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let og_description = page
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.opengraph
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.properties
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.get("description")
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.map(|t| t.to_string());
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let og_title = page
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.opengraph
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.properties
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.get("title")
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.map(|t| t.to_string());
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let og_image = page
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.opengraph
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.images
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.get(0)
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.and_then(|ogo| Url::parse(&ogo.url).ok());
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let title = og_title.or(page_title);
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let description = og_description.or(page_description);
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let image = og_image;
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Ok(SiteMetadata {
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title,
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description,
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image,
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html: None,
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})
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}
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#[derive(Deserialize, Debug, Clone)]
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pub(crate) struct PictrsResponse {
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files: Vec<PictrsFile>,
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msg: String,
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}
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#[derive(Deserialize, Debug, Clone)]
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pub(crate) struct PictrsFile {
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file: String,
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#[allow(dead_code)]
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delete_token: String,
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}
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#[tracing::instrument(skip_all)]
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pub(crate) async fn fetch_pictrs(
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client: &ClientWithMiddleware,
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settings: &Settings,
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image_url: &Url,
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) -> Result<PictrsResponse, LemmyError> {
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if let Some(pictrs_url) = settings.pictrs_url.to_owned() {
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is_image_content_type(client, image_url).await?;
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let fetch_url = format!(
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"{}/image/download?url={}",
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pictrs_url,
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utf8_percent_encode(image_url.as_str(), NON_ALPHANUMERIC) // TODO this might not be needed
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);
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let response = client
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.get(&fetch_url)
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.timeout(REQWEST_TIMEOUT)
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.send()
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.await?;
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let response: PictrsResponse = response
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.json()
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.await
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.map_err(|e| RecvError(e.to_string()))?;
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if response.msg == "ok" {
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Ok(response)
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} else {
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Err(anyhow!("{}", &response.msg).into())
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}
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} else {
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Err(anyhow!("pictrs_url not set up in config").into())
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}
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}
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/// Both are options, since the URL might be either an html page, or an image
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/// Returns the SiteMetadata, and a Pictrs URL, if there is a picture associated
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#[tracing::instrument(skip_all)]
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pub async fn fetch_site_data(
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client: &ClientWithMiddleware,
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settings: &Settings,
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url: Option<&Url>,
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) -> (Option<SiteMetadata>, Option<Url>) {
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match &url {
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Some(url) => {
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// Fetch metadata
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// Ignore errors, since it may be an image, or not have the data.
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// Warning, this may ignore SSL errors
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let metadata_option = fetch_site_metadata(client, url).await.ok();
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// Fetch pictrs thumbnail
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let pictrs_hash = match &metadata_option {
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Some(metadata_res) => match &metadata_res.image {
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// Metadata, with image
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// Try to generate a small thumbnail if there's a full sized one from post-links
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Some(metadata_image) => fetch_pictrs(client, settings, metadata_image)
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.await
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.map(|r| r.files[0].file.to_owned()),
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// Metadata, but no image
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None => fetch_pictrs(client, settings, url)
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.await
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.map(|r| r.files[0].file.to_owned()),
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},
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// No metadata, try to fetch the URL as an image
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None => fetch_pictrs(client, settings, url)
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.await
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.map(|r| r.files[0].file.to_owned()),
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};
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// The full urls are necessary for federation
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let pictrs_thumbnail = pictrs_hash
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.map(|p| {
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Url::parse(&format!(
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"{}/pictrs/image/{}",
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settings.get_protocol_and_hostname(),
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p
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))
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.ok()
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})
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.ok()
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.flatten();
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(metadata_option, pictrs_thumbnail)
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}
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None => (None, None),
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}
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}
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#[tracing::instrument(skip_all)]
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async fn is_image_content_type(client: &ClientWithMiddleware, url: &Url) -> Result<(), LemmyError> {
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let response = client
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.get(url.as_str())
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.timeout(REQWEST_TIMEOUT)
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.send()
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.await?;
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if response
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.headers()
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.get("Content-Type")
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.ok_or_else(|| anyhow!("No Content-Type header"))?
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.to_str()?
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.starts_with("image/")
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{
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Ok(())
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} else {
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Err(anyhow!("Not an image type.").into())
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}
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}
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pub fn build_user_agent(settings: &Settings) -> String {
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format!(
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"Lemmy/{}; +{}",
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VERSION,
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settings.get_protocol_and_hostname()
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)
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}
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#[cfg(test)]
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mod tests {
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use crate::request::{build_user_agent, fetch_site_metadata};
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use url::Url;
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use super::SiteMetadata;
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use crate::settings::structs::Settings;
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// These helped with testing
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#[actix_rt::test]
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async fn test_site_metadata() {
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let settings = Settings::init().unwrap();
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let client = reqwest::Client::builder()
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.user_agent(build_user_agent(&settings))
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.build()
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.unwrap()
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.into();
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let sample_url = Url::parse("https://gitlab.com/IzzyOnDroid/repo/-/wikis/FAQ").unwrap();
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let sample_res = fetch_site_metadata(&client, &sample_url).await.unwrap();
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assert_eq!(
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SiteMetadata {
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title: Some("FAQ · Wiki · IzzyOnDroid / repo · GitLab".to_string()),
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description: Some(
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"The F-Droid compatible repo at https://apt.izzysoft.de/fdroid/".to_string()
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),
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image: Some(
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Url::parse("https://gitlab.com/uploads/-/system/project/avatar/4877469/iod_logo.png")
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.unwrap()
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),
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html: None,
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},
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sample_res
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);
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let youtube_url = Url::parse("https://www.youtube.com/watch?v=IquO_TcMZIQ").unwrap();
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let youtube_res = fetch_site_metadata(&client, &youtube_url).await.unwrap();
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assert_eq!(
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SiteMetadata {
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title: Some("A Hard Look at Rent and Rent Seeking with Michael Hudson & Pepe Escobar".to_string()),
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description: Some("An interactive discussion on wealth inequality and the “Great Game” on the control of natural resources.In this webinar organized jointly by the Henry George...".to_string()),
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image: Some(Url::parse("https://i.ytimg.com/vi/IquO_TcMZIQ/maxresdefault.jpg").unwrap()),
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html: None,
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}, youtube_res);
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}
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// #[test]
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// fn test_pictshare() {
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// let res = fetch_pictshare("https://upload.wikimedia.org/wikipedia/en/2/27/The_Mandalorian_logo.jpg");
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// assert!(res.is_ok());
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// let res_other = fetch_pictshare("https://upload.wikimedia.org/wikipedia/en/2/27/The_Mandalorian_logo.jpgaoeu");
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// assert!(res_other.is_err());
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// }
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}
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