79 lines
2.6 KiB
Rust
79 lines
2.6 KiB
Rust
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//! This module provides the functionality to cache the aggregated results fetched and aggregated
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//! from the upstream search engines in a json format.
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use md5::compute;
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use redis::{Client, Commands, Connection};
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/// A named struct which stores the redis Connection url address to which the client will
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/// connect to.
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///
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/// # Fields
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///
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/// * `redis_connection_url` - It stores the redis Connection url address.
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#[derive(Clone)]
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pub struct RedisCache {
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redis_connection_url: String,
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}
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impl RedisCache {
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/// Constructs a new `SearchResult` with the given arguments needed for the struct.
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///
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/// # Arguments
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///
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/// * `redis_connection_url` - It stores the redis Connection url address.
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pub fn new(redis_connection_url: String) -> Self {
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RedisCache {
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redis_connection_url,
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}
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}
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/// A helper function which computes the hash of the url and formats and returns it as string.
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///
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/// # Arguments
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///
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/// * `url` - It takes an url as string.
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fn compute_url_hash(self, url: &str) -> String {
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format!("{:?}", compute(url))
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}
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/// A function which fetches the cached json results as json string from the redis server.
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///
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/// # Arguments
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///
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/// * `url` - It takes an url as a string.
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pub fn cached_results_json(self, url: String) -> Result<String, Box<dyn std::error::Error>> {
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let hashed_url_string = self.clone().compute_url_hash(&url);
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let mut redis_connection: Connection =
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Client::open(self.redis_connection_url)?.get_connection()?;
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Ok(redis_connection.get(hashed_url_string)?)
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}
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/// A function which caches the results by using the hashed `url` as the key and
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/// `json results` as the value and stores it in redis server with ttl(time to live)
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/// set to 60 seconds.
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///
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/// # Arguments
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///
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/// * `json_results` - It takes the json results string as an argument.
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/// * `url` - It takes the url as a String.
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pub fn cache_results(
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self,
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json_results: String,
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url: String,
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) -> Result<(), Box<dyn std::error::Error>> {
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let hashed_url_string = self.clone().compute_url_hash(&url);
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let mut redis_connection: Connection =
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Client::open(self.redis_connection_url)?.get_connection()?;
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// put results_json into cache
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redis_connection.set(hashed_url_string.clone(), json_results)?;
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// Set the TTL for the key to 60 seconds
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redis_connection
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.expire::<String, u32>(hashed_url_string.clone(), 60)
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.unwrap();
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Ok(())
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}
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}
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