RosettaCodeData/Task/Rosetta-Code-Find-unimpleme.../Rust/rosetta-code-find-unimpleme...

142 lines
4.2 KiB
Plaintext

use std::collections::{BTreeMap, HashSet};
use reqwest::Url;
use serde::Deserialize;
use serde_json::Value;
/// A Rosetta Code task.
#[derive(Clone, PartialEq, Eq, Hash, Debug, Deserialize)]
pub struct Task {
/// The ID of the page containing the task in the MediaWiki API.
#[serde(rename = "pageid")]
pub id: u64,
/// The human-readable title of the task.
pub title: String,
}
/// Encapsulates errors that might occur during JSON parsing.
#[derive(Debug)]
enum TaskParseError {
/// Something went wrong with the HTTP request to the API.
Http(reqwest::Error),
/// There was a problem parsing the API response into JSON.
Json(serde_json::Error),
/// The response JSON contained unexpected keys or values.
UnexpectedFormat,
}
impl From<serde_json::Error> for TaskParseError {
fn from(err: serde_json::Error) -> Self {
TaskParseError::Json(err)
}
}
impl From<reqwest::Error> for TaskParseError {
fn from(err: reqwest::Error) -> Self {
TaskParseError::Http(err)
}
}
/// Represents a category of pages on Rosetta Code, such as "Rust".
struct Category {
name: String,
continue_params: Option<BTreeMap<String, String>>,
}
impl Category {
fn new(name: &str) -> Category {
let mut continue_params = BTreeMap::new();
continue_params.insert("continue".to_owned(), "".to_owned());
Category {
name: name.to_owned(),
continue_params: Some(continue_params),
}
}
}
/// Sends a request to Rosetta Code through the MediaWiki API. If successful, returns the response
/// as a JSON object.
fn query_api(
category_name: &str,
continue_params: &BTreeMap<String, String>,
) -> Result<Value, TaskParseError> {
let mut url = Url::parse("http://rosettacode.org/mw/api.php").expect("invalid URL");
url.query_pairs_mut()
.append_pair("action", "query")
.append_pair("list", "categorymembers")
.append_pair("cmtitle", &format!("Category:{}", category_name))
.append_pair("cmlimit", "500")
.append_pair("format", "json")
.extend_pairs(continue_params);
Ok(reqwest::blocking::get(url)?.json()?)
}
/// Given a JSON object, parses the task information from the MediaWiki API response.
fn parse_tasks(json: &Value) -> Result<Vec<Task>, TaskParseError> {
let tasks_json = json
.pointer("/query/categorymembers")
.and_then(Value::as_array)
.ok_or(TaskParseError::UnexpectedFormat)?;
tasks_json
.iter()
.map(|json| Task::deserialize(json).map_err(From::from))
.collect()
}
impl Iterator for Category {
type Item = Vec<Task>;
fn next(&mut self) -> Option<Self::Item> {
self.continue_params.as_ref()?;
query_api(&self.name, self.continue_params.as_ref()?)
.and_then(|result| {
// If there are more pages of results to request, save them for the next iteration.
self.continue_params =
result
.get("continue")
.and_then(Value::as_object)
.map(|continue_params| {
continue_params
.iter()
.map(|(key, value)| {
(key.to_owned(), value.as_str().unwrap().to_owned())
})
.collect()
});
parse_tasks(&result)
})
.map_err(|err| println!("Error parsing response: {:?}", err))
.ok()
}
}
pub fn all_tasks() -> Vec<Task> {
Category::new("Programming Tasks").flatten().collect()
}
pub fn unimplemented_tasks(lang: &str) -> Vec<Task> {
let all_tasks = all_tasks().iter().cloned().collect::<HashSet<_>>();
let implemented_tasks = Category::new(lang).flatten().collect::<HashSet<_>>();
let mut unimplemented_tasks = all_tasks
.difference(&implemented_tasks)
.cloned()
.collect::<Vec<Task>>();
unimplemented_tasks.sort_by(|a, b| a.title.cmp(&b.title));
unimplemented_tasks
}
fn main() {
for task in find_unimplemented_tasks::unimplemented_tasks("Rust") {
println!("{:6} {}", task.id, task.title);
}
}