Add topic parsing.

This commit is contained in:
Bauke 2023-06-21 11:59:38 +02:00
parent a2b9efb94b
commit 773a075edf
Signed by: Bauke
GPG Key ID: C1C0F29952BCF558
4 changed files with 198 additions and 1 deletions

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@ -4,12 +4,13 @@ use std::str::FromStr;
use {duplicate::duplicate_item, scraper::Html}; use {duplicate::duplicate_item, scraper::Html};
use crate::{Group, GroupList, ParseError}; use crate::{Group, GroupList, ParseError, Topic};
#[duplicate_item( #[duplicate_item(
_Struct; _Struct;
[Group]; [Group];
[GroupList]; [GroupList];
[Topic];
)] )]
impl FromStr for _Struct { impl FromStr for _Struct {
type Err = ParseError; type Err = ParseError;

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@ -28,9 +28,11 @@ pub(crate) mod error;
pub(crate) mod from_str; pub(crate) mod from_str;
pub(crate) mod group; pub(crate) mod group;
pub(crate) mod group_list; pub(crate) mod group_list;
pub(crate) mod topic;
pub use { pub use {
error::*, error::*,
group::{Group, GroupWikiLink}, group::{Group, GroupWikiLink},
group_list::{GroupList, GroupListSummary}, group_list::{GroupList, GroupListSummary},
topic::*,
}; };

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@ -28,4 +28,28 @@ lazy_static! {
/// Selector for group wiki links. /// Selector for group wiki links.
pub static ref GROUP_WIKI_LINKS: Selector = selector(r#"#sidebar [href*="/wiki/"]"#); pub static ref GROUP_WIKI_LINKS: Selector = selector(r#"#sidebar [href*="/wiki/"]"#);
/// Selector for the topic comment count.
pub static ref TOPIC_COMMENT_COUNT: Selector = selector(".topic-comments-header h2");
/// Selector for the topic full byline.
pub static ref TOPIC_FULL_BYLINE: Selector = selector(".topic-full-byline");
/// Selector for a link topic's content.
pub static ref TOPIC_FULL_LINK: Selector = selector(".topic-full-link a");
/// Selector for the topic tag elements.
pub static ref TOPIC_FULL_TAGS: Selector = selector(".topic-full-tags a");
/// Selector for a text topic's content.
pub static ref TOPIC_FULL_TEXT: Selector = selector(".topic-full-text");
/// Selector for the main topic `<article>`.
pub static ref TOPIC_MAIN_ARTICLE: Selector = selector("main > .topic-full");
/// Selector for a topic toast warning.
pub static ref TOPIC_TOAST_WARNING: Selector = selector(".toast.toast-warning");
/// Selector for the topic vote count.
pub static ref TOPIC_VOTE_COUNT: Selector = selector(".topic-voting-votes");
} }

170
source/topic.rs Normal file
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@ -0,0 +1,170 @@
//! Parsing for `/~<group>/<topic-id>`.
use scraper::Html;
use crate::{
regexes::DUPLICATE_WHITESPACE_RE,
selectors::{
TOPIC_COMMENT_COUNT, TOPIC_FULL_BYLINE, TOPIC_FULL_LINK, TOPIC_FULL_TAGS,
TOPIC_FULL_TEXT, TOPIC_MAIN_ARTICLE, TOPIC_TOAST_WARNING, TOPIC_VOTE_COUNT,
},
utilities::select_first_element_text,
ParseError,
};
/// A Tildes topic.
#[derive(Debug)]
pub struct Topic {
/// The name of the author.
pub author: TopicAuthor,
/// The amount of comments the topic has. Comments themselves have to be
/// parsed separately.
pub comment_total: i32,
/// The content of the topic.
pub content: TopicContent,
/// The unique ID of the topic.
pub id: String,
/// Whether the topic is locked.
pub is_locked: bool,
/// Whether the topic is official (not yet implemented, is always false).
///
/// TODO: Add is_official. This isn't possible right now because topics don't
/// have any indicator of being marked as official. The only place it's shown
/// is in the topic listing. See #787 in the Tildes issue tracker.
pub is_official: bool,
/// All tags applied to the topic.
pub tags: Vec<String>,
/// The amount of votes the topic has received.
pub vote_count: i32,
}
/// All the different ways a topic author can be represented.
#[derive(Debug)]
pub enum TopicAuthor {
/// The normal case, where the topic author is available.
Name(String),
/// The topic was posted by Tildes itself.
///
/// Technically the user for this is [Tildes](https://tildes.net/user/tildes)
/// but in the topic it says "Automatically posted <date>" where the username
/// normally goes, so may as well special-case it here too.
Scheduled,
/// The user was banned, deleted their account or disassociated the topic from
/// their account.
Unknown,
}
/// The different types of content a topic can have.
#[derive(Debug)]
pub enum TopicContent {
/// The topic is a link topic pointing to an external site.
Link(String),
/// The topic is a text topic with a HTML body.
Text(String),
/// The topic's content is no longer available.
Unknown,
}
impl Topic {
/// Parses a [`Topic`] from a [`scraper::Html`] tree.
pub fn from_html(html: &Html) -> Result<Self, ParseError> {
let topic_article_element = html
.select(&TOPIC_MAIN_ARTICLE)
.next()
.ok_or(ParseError::MissingExpectedHtml)?;
let topic_byline =
select_first_element_text(topic_article_element, &TOPIC_FULL_BYLINE)
.map(|byline| {
DUPLICATE_WHITESPACE_RE
.replace_all(&byline, " ")
.to_string()
})
.ok_or(ParseError::MissingExpectedHtml)?;
let author = if topic_byline.starts_with("Automatically posted") {
TopicAuthor::Scheduled
} else if topic_byline.ends_with("unknown user") {
TopicAuthor::Unknown
} else {
TopicAuthor::Name(
topic_byline
.split(" ")
.last()
.ok_or(ParseError::MissingExpectedHtml)?
.to_string(),
)
};
let comment_total = if let Some(comment_total) =
select_first_element_text(topic_article_element, &TOPIC_COMMENT_COUNT)
{
comment_total
.split(" ")
.next()
.map(|count| count.parse::<i32>())
.ok_or(ParseError::MissingExpectedHtml)?
.map_err(|_| ParseError::MissingExpectedHtml)?
} else {
0
};
let content = if let Some(link_content) =
topic_article_element.select(&TOPIC_FULL_LINK).next()
{
TopicContent::Link(link_content.text().collect::<String>())
} else if let Some(text_content) =
topic_article_element.select(&TOPIC_FULL_TEXT).next()
{
TopicContent::Text(text_content.inner_html().trim().to_string())
} else {
TopicContent::Unknown
};
let id = topic_article_element
.value()
.id()
.ok_or(ParseError::MissingExpectedHtml)?[6..]
.to_string();
let is_locked =
select_first_element_text(topic_article_element, &TOPIC_TOAST_WARNING)
.map(|toast| toast.contains("This topic is locked."))
.unwrap_or_default();
let tags = topic_article_element
.select(&TOPIC_FULL_TAGS)
.map(|tag| tag.text().collect::<String>())
.collect::<Vec<_>>();
let vote_count =
select_first_element_text(topic_article_element, &TOPIC_VOTE_COUNT)
.map(|vote_count| vote_count.parse::<i32>())
.ok_or(ParseError::MissingExpectedHtml)?
.map_err(|_| ParseError::MissingExpectedHtml)?;
let topic = Topic {
author,
comment_total,
content,
id,
is_locked,
is_official: false, // TODO: Implement this once it can be done.
tags,
vote_count,
};
Ok(topic)
}
}