File size: 2,636 Bytes
c170de8 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 |
//! This module provides the functionality to cache the aggregated results fetched and aggregated
//! from the upstream search engines in a json format.
use md5::compute;
use redis::{Client, Commands, Connection};
/// A named struct which stores the redis Connection url address to which the client will
/// connect to.
///
/// # Fields
///
/// * `redis_connection_url` - It stores the redis Connection url address.
#[derive(Clone)]
pub struct RedisCache {
redis_connection_url: String,
}
impl RedisCache {
/// Constructs a new `SearchResult` with the given arguments needed for the struct.
///
/// # Arguments
///
/// * `redis_connection_url` - It stores the redis Connection url address.
pub fn new(redis_connection_url: String) -> Self {
RedisCache {
redis_connection_url,
}
}
/// A helper function which computes the hash of the url and formats and returns it as string.
///
/// # Arguments
///
/// * `url` - It takes an url as string.
fn compute_url_hash(self, url: &str) -> String {
format!("{:?}", compute(url))
}
/// A function which fetches the cached json results as json string from the redis server.
///
/// # Arguments
///
/// * `url` - It takes an url as a string.
pub fn cached_results_json(self, url: String) -> Result<String, Box<dyn std::error::Error>> {
let hashed_url_string = self.clone().compute_url_hash(&url);
let mut redis_connection: Connection =
Client::open(self.redis_connection_url)?.get_connection()?;
Ok(redis_connection.get(hashed_url_string)?)
}
/// A function which caches the results by using the hashed `url` as the key and
/// `json results` as the value and stores it in redis server with ttl(time to live)
/// set to 60 seconds.
///
/// # Arguments
///
/// * `json_results` - It takes the json results string as an argument.
/// * `url` - It takes the url as a String.
pub fn cache_results(
self,
json_results: String,
url: String,
) -> Result<(), Box<dyn std::error::Error>> {
let hashed_url_string = self.clone().compute_url_hash(&url);
let mut redis_connection: Connection =
Client::open(self.redis_connection_url)?.get_connection()?;
// put results_json into cache
redis_connection.set(hashed_url_string.clone(), json_results)?;
// Set the TTL for the key to 60 seconds
redis_connection
.expire::<String, u32>(hashed_url_string.clone(), 60)
.unwrap();
Ok(())
}
}
|