Abstract over Cache

Add `Cache` trait and implement it for the `Cacache` and `DummyCache`.
Fix tests to use the DummyCache, dropping old dependencies.
See #11.

Cargo.lock

@@ -990,9 +990,9 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_plain",
+ "ssri",
  "structopt",
  "strum",
- "temp-dir",
  "terminal_size",
  "textwrap 0.14.2",
  "thiserror",
@@ -1762,12 +1762,6 @@ dependencies = [
  "unicode-xid",
 ]
 
-[[package]]
-name = "temp-dir"
-version = "0.1.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af547b166dd1ea4b472165569fc456cfb6818116f854690b0ff205e636523dab"
-
 [[package]]
 name = "tempfile"
 version = "3.2.0"

Cargo.toml

@@ -37,6 +37,6 @@ serde_json = "1.0"
 itertools = "0.10"
 
 [dev-dependencies]
-temp-dir = "0.1"
 pretty_assertions = "1.0"
+ssri = "7.0"
 assert_cmd = "2.0"

src/cache/cacache.rs

@@ -0,0 +1,67 @@
+use std::{io::Write, path::PathBuf};
+
+use cacache::Metadata;
+use itertools::Itertools;
+use lazy_static::lazy_static;
+use tracing::info;
+
+use super::Cache;
+
+use crate::{
+    error::{Error, Result},
+    request::Headers,
+    DIR,
+};
+
+lazy_static! {
+    /// Path to the cache.
+    static ref CACHE: PathBuf  = DIR.cache_dir().into();
+}
+
+pub struct Cacache;
+
+impl Cache for Cacache
+where
+    Self: Sized,
+{
+    fn init() -> Result<Self> {
+        Ok(Cacache)
+    }
+
+    fn write(&self, headers: &Headers, url: &str, text: &str) -> Result<()> {
+        let header_serialized = serde_json::to_value(headers.clone())
+            .map_err(|why| Error::Serializing(why, "writing headers to cache"))?;
+        let mut writer = cacache::WriteOpts::new()
+            .metadata(header_serialized)
+            .open_sync(&*CACHE, url)
+            .map_err(|why| Error::Cache(why, "opening for write"))?;
+        writer
+            .write_all(text.as_bytes())
+            .map_err(|why| Error::Io(why, "writing value"))?;
+        writer
+            .commit()
+            .map_err(|why| Error::Cache(why, "commiting write"))?;
+        info!("Updated cache for {:?}", url);
+        Ok(())
+    }
+
+    fn read(&self, meta: &Metadata) -> Result<String> {
+        cacache::read_hash_sync(&*CACHE, &meta.integrity)
+            .map_err(|why| Error::Cache(why, "reading value"))
+            .and_then(|raw| String::from_utf8(raw).map_err(Error::DecodingUtf8))
+    }
+
+    fn meta(&self, url: &str) -> Result<Option<Metadata>> {
+        cacache::metadata_sync(&*CACHE, url).map_err(|why| Error::Cache(why, "reading metadata"))
+    }
+
+    fn clear(&self) -> Result<()> {
+        cacache::clear_sync(&*CACHE).map_err(|why| Error::Cache(why, "clearing"))
+    }
+
+    fn list(&self) -> Result<Vec<Metadata>> {
+        cacache::list_sync(&*CACHE)
+            .map(|res| res.map_err(|why| Error::Cache(why, "listing")))
+            .try_collect()
+    }
+}

src/cache/dummy.rs

@@ -0,0 +1,114 @@
+use std::{collections::BTreeMap, sync::RwLock};
+
+use cacache::Metadata;
+use ssri::{Hash, Integrity};
+
+use super::Cache;
+
+use crate::{
+    error::{Error, Result},
+    request::Headers,
+};
+
+struct Entry {
+    meta: Metadata,
+    text: String,
+}
+
+pub struct DummyCache {
+    /// The real, cacache-based implementation takes only immutable references
+    /// and the API is adopted to handle that. Thus we'll have to do our
+    /// own interior mutability here.
+    content: RwLock<BTreeMap<Hash, Entry>>,
+}
+
+impl Cache for DummyCache {
+    fn init() -> Result<Self> {
+        Ok(DummyCache {
+            content: RwLock::new(BTreeMap::new()),
+        })
+    }
+
+    fn read(&self, meta: &Metadata) -> Result<String> {
+        let (algorithm, digest) = meta.integrity.to_hex();
+        let hash = Hash { algorithm, digest };
+        let read = self.content.read().expect("Reading cache failed");
+        let entry = read
+            .get(&hash)
+            .expect("BUG: Metadata exists, but entry does not!");
+        Ok(entry.text.clone())
+    }
+
+    fn write(&self, headers: &Headers, url: &str, text: &str) -> Result<()> {
+        let mut write = self.content.write().expect("Writing cache failed");
+        let hash = hash_from_key(url);
+        let meta = assemble_meta(headers, url, text)?;
+        write.insert(
+            hash,
+            Entry {
+                meta,
+                text: text.to_owned(),
+            },
+        );
+        Ok(())
+    }
+
+    fn meta(&self, url: &str) -> Result<Option<Metadata>> {
+        let hash = hash_from_key(url);
+        match self
+            .content
+            .read()
+            .expect("Reading cache failed")
+            .get(&hash)
+        {
+            Some(entry) => Ok(Some(clone_metadata(&entry.meta))),
+            None => Ok(None),
+        }
+    }
+
+    fn clear(&self) -> Result<()> {
+        self.content.write().expect("Writing cache failed").clear();
+        Ok(())
+    }
+
+    fn list(&self) -> Result<Vec<Metadata>> {
+        let read = self.content.read().expect("Reading cache failed");
+        let list = read
+            .values()
+            .map(|entry| clone_metadata(&entry.meta))
+            .collect();
+        Ok(list)
+    }
+}
+
+fn hash_from_key(key: &str) -> Hash {
+    let integrity = Integrity::from(key);
+    hash_from_integrity(&integrity)
+}
+
+fn hash_from_integrity(integrity: &Integrity) -> Hash {
+    let (algorithm, digest) = integrity.to_hex();
+    Hash { algorithm, digest }
+}
+
+fn clone_metadata(meta: &Metadata) -> Metadata {
+    Metadata {
+        key: meta.key.clone(),
+        integrity: meta.integrity.clone(),
+        time: meta.time,
+        size: meta.size,
+        metadata: meta.metadata.clone(),
+    }
+}
+
+fn assemble_meta(headers: &Headers, url: &str, text: &str) -> Result<Metadata> {
+    let time = chrono::Utc::now();
+    Ok(Metadata {
+        key: url.to_owned(),
+        integrity: Integrity::from(url),
+        time: time.timestamp_millis() as u128,
+        size: text.len(),
+        metadata: serde_json::to_value(headers)
+            .map_err(|why| Error::Serializing(why, "converting headers to json"))?,
+    })
+}

src/cache/mod.rs

@@ -28,7 +28,7 @@
 //! - `fetch` functions are generalized over web requests and cache loading.
 //! - `get` functions only operate on requests.
 //! - `load`, `update` functions only operate on the cache.
-use cacache::Metadata;
+use ::cacache::Metadata;
 use chrono::{Duration, TimeZone};
 use lazy_static::lazy_static;
 use reqwest::{StatusCode, Url};
@@ -38,10 +38,18 @@ use tracing::{info, warn};
 mod fetchable;
 #[cfg(test)]
 mod tests;
-mod wrapper;
+
+#[cfg(not(test))]
+mod cacache;
+#[cfg(not(test))]
+use self::cacache::Cacache as DefaultCache;
+
+#[cfg(test)]
+mod dummy;
+#[cfg(test)]
+use self::dummy::DummyCache as DefaultCache;
 
 pub use fetchable::Fetchable;
-pub use wrapper::clear_cache as clear;
 
 use crate::{
     error::{Error, Result, ResultExt},
@@ -51,6 +59,10 @@ use crate::{
 /// Returned by most functions in this module.
 type TextAndHeaders = (String, Headers);
 
+lazy_static! {
+    pub static ref CACHE: DefaultCache = DefaultCache::init().expect("Initialized cache");
+}
+
 /// Possible results from a cache load.
 #[derive(Debug, PartialEq)]
 enum CacheResult<T> {
@@ -62,77 +74,113 @@ enum CacheResult<T> {
     Hit(T),
 }
 
-/// Wrapper around [`fetch`] for responses that contain json.
-pub fn fetch_json<S, T>(url: S, local_ttl: Duration) -> Result<T>
+/// Cache trait
+///
+/// Generalized over the default Cacache and a DummyCache used for tests.
+pub trait Cache
 where
-    S: AsRef<str>,
-    T: DeserializeOwned,
+    Self: Sized,
 {
-    fetch(url, local_ttl, |text, _| {
-        // TODO: Check content header?
-        serde_json::from_str(&text).map_err(|why| Error::Deserializing(why, "fetching json"))
-    })
-}
+    /// Initialize the cache.
+    fn init() -> Result<Self>;
 
-/// Generic method for fetching remote url-based resources that may be cached.
-pub fn fetch<Map, S, T>(url: S, local_ttl: Duration, map: Map) -> Result<T>
-where
-    S: AsRef<str>,
-    Map: FnOnce(String, Headers) -> Result<T>,
-{
-    // Normalize the url at this point since we're using it
-    // as the cache key
-    let url = Url::parse(url.as_ref()).map_err(|_| Error::InternalUrl)?;
-    let url = url.as_ref();
-    info!("Fetching {:?}", url);
-    // Try getting the value from cache, if that fails, query the web
-    let (text, headers) = match try_load_cache(url, local_ttl) {
-        Ok(CacheResult::Hit(text_and_headers)) => {
-            info!("Hit cache on {:?}", url);
-            text_and_headers
-        }
-        Ok(CacheResult::Miss) => {
-            info!("Missed cache on {:?}", url);
-            get_and_update_cache(url, None, None)?
-        }
-        Ok(CacheResult::Stale(old_headers, meta)) => {
-            info!("Stale cache on {:?}", url);
-            // The cache is stale but may still be valid
-            // Request the resource with set IF_NONE_MATCH tag and update
-            // the caches metadata or value
-            match get_and_update_cache(url, old_headers.etag, Some(meta)) {
-                Ok(tah) => tah,
-                Err(why) => {
-                    warn!("{}", why);
-                    // Fetching and updating failed for some reason, retry
-                    // without the IF_NONE_MATCH tag and fail if unsuccessful
-                    get_and_update_cache(url, None, None)?
+    /// Read from the cache.
+    fn read(&self, meta: &Metadata) -> Result<String>;
+
+    /// Write to the cache.
+    ///
+    /// The `url` is used as key and the `text` as value for the entry.
+    /// The `headers` are attached as additional metadata.
+    fn write(&self, headers: &Headers, url: &str, text: &str) -> Result<()>;
+
+    /// Get the [`Metadata`] for the cache entry.
+    fn meta(&self, url: &str) -> Result<Option<Metadata>>;
+
+    /// Clear all entries from the cache.
+    fn clear(&self) -> Result<()>;
+
+    /// List all cache entries.
+    fn list(&self) -> Result<Vec<Metadata>>;
+
+    /// Wrapper around [`fetch`] for responses that contain json.
+    fn fetch_json<S, T>(&self, url: S, local_ttl: Duration) -> Result<T>
+    where
+        S: AsRef<str>,
+        T: DeserializeOwned,
+    {
+        self.fetch(url, local_ttl, |text, _| {
+            // TODO: Check content header?
+            serde_json::from_str(&text).map_err(|why| Error::Deserializing(why, "fetching json"))
+        })
+    }
+
+    /// Generic method for fetching remote url-based resources that may be cached.
+    ///
+    /// This is the preferred way to access the cache, as the requested value
+    /// will be fetched from the inter-webs if the cache misses.
+    fn fetch<Map, S, T>(&self, url: S, local_ttl: Duration, map: Map) -> Result<T>
+    where
+        S: AsRef<str>,
+        Map: FnOnce(String, Headers) -> Result<T>,
+    {
+        // Normalize the url at this point since we're using it
+        // as the cache key
+        let url = Url::parse(url.as_ref()).map_err(|_| Error::InternalUrl)?;
+        let url = url.as_ref();
+        info!("Fetching {:?}", url);
+        // Try getting the value from cache, if that fails, query the web
+        let (text, headers) = match try_load_cache(self, url, local_ttl) {
+            Ok(CacheResult::Hit(text_and_headers)) => {
+                info!("Hit cache on {:?}", url);
+                text_and_headers
+            }
+            Ok(CacheResult::Miss) => {
+                info!("Missed cache on {:?}", url);
+                get_and_update_cache(self, url, None, None)?
+            }
+            Ok(CacheResult::Stale(old_headers, meta)) => {
+                info!("Stale cache on {:?}", url);
+                // The cache is stale but may still be valid
+                // Request the resource with set IF_NONE_MATCH tag and update
+                // the caches metadata or value
+                match get_and_update_cache(self, url, old_headers.etag, Some(meta)) {
+                    Ok(tah) => tah,
+                    Err(why) => {
+                        warn!("{}", why);
+                        // Fetching and updating failed for some reason, retry
+                        // without the IF_NONE_MATCH tag and fail if unsuccessful
+                        get_and_update_cache(self, url, None, None)?
+                    }
                 }
             }
-        }
-        Err(why) => {
-            // Fetching from the cache failed for some reason, just
-            // request the resource and update the cache
-            warn!("{}", why);
-            get_and_update_cache(url, None, None)?
-        }
-    };
-    // Apply the map and return the result
-    map(text, headers)
+            Err(why) => {
+                // Fetching from the cache failed for some reason, just
+                // request the resource and update the cache
+                warn!("{}", why);
+                get_and_update_cache(self, url, None, None)?
+            }
+        };
+        // Apply the map and return the result
+        map(text, headers)
+    }
 }
 
 /// Try loading the cache content.
 ///
 /// This can fail due to errors, but also exits with a [`CacheResult`].
-fn try_load_cache(url: &str, local_ttl: Duration) -> Result<CacheResult<TextAndHeaders>> {
+fn try_load_cache<C: Cache>(
+    cache: &C,
+    url: &str,
+    local_ttl: Duration,
+) -> Result<CacheResult<TextAndHeaders>> {
     // Try reading the cache's metadata
-    match wrapper::read_cache_meta(url)? {
+    match cache.meta(url)? {
         Some(meta) => {
             // Metadata exists
             if is_fresh(&meta, &local_ttl) {
                 // Fresh, try to fetch from cache
-                let raw = wrapper::read_cache(&meta)?;
-                to_text_and_headers(raw, &meta.metadata).map(CacheResult::Hit)
+                let text = cache.read(&meta)?;
+                to_text_and_headers(text, &meta.metadata).map(CacheResult::Hit)
             } else {
                 // Local check failed, but the value may still be valid
                 let old_headers = headers_from_metadata(&meta)?;
@@ -152,7 +200,8 @@ fn try_load_cache(url: &str, local_ttl: Duration) -> Result<CacheResult<TextAndH
 ///
 /// If an optional `etag` is provided, add the If-None-Match header, and thus
 /// only get an update if the new ETAG differs from the given `etag`.
-fn get_and_update_cache(
+fn get_and_update_cache<C: Cache>(
+    cache: &C,
     url: &str,
     etag: Option<String>,
     meta: Option<Metadata>,
@@ -167,11 +216,11 @@ fn get_and_update_cache(
         Some(meta) if resp.status == StatusCode::NOT_MODIFIED => {
             // If we received code 304 NOT MODIFIED (after adding the If-None-Match)
             // our cache is actually fresh and it's timestamp should be updated
-            touch_and_load_cache(url, &meta, resp.headers)
+            touch_and_load_cache(cache, url, &meta, resp.headers)
         }
         _ if resp.status.is_success() => {
             // Request returned successfully, now update the cache with that
-            update_cache_from_response(resp)
+            update_cache_from_response(cache, resp)
         }
         _ => {
             // Some error occured, just error out
@@ -184,19 +233,24 @@ fn get_and_update_cache(
 /// Extract body and headers from response and update the cache.
 ///
 /// Only relevant headers will be kept.
-fn update_cache_from_response(resp: Response) -> Result<TextAndHeaders> {
+fn update_cache_from_response<C: Cache>(cache: &C, resp: Response) -> Result<TextAndHeaders> {
     let url = resp.url.to_owned();
-    wrapper::write_cache(&resp.headers, &url, &resp.body)?;
+    cache.write(&resp.headers, &url, &resp.body)?;
     Ok((resp.body, resp.headers))
 }
 
 /// Reset the cache's TTL, load and return it.
-fn touch_and_load_cache(url: &str, meta: &Metadata, headers: Headers) -> Result<TextAndHeaders> {
-    let raw = wrapper::read_cache(meta)?;
+fn touch_and_load_cache<C: Cache>(
+    cache: &C,
+    url: &str,
+    meta: &Metadata,
+    headers: Headers,
+) -> Result<TextAndHeaders> {
+    let raw = cache.read(meta)?;
     let (text, _) = to_text_and_headers(raw, &meta.metadata)?;
     // TODO: Update the timestamp in a smarter way..
     // Do not fall on errors, this doesn’t matter
-    wrapper::write_cache(&headers, url, &text).log_warn();
+    cache.write(&headers, url, &text).log_warn();
     Ok((text, headers))
 }
 
@@ -215,10 +269,9 @@ fn is_fresh(meta: &Metadata, local_ttl: &Duration) -> bool {
 }
 
 /// Helper to convert raw text and serialized json to [`TextAndHeaders`].
-fn to_text_and_headers(raw: Vec<u8>, meta: &serde_json::Value) -> Result<TextAndHeaders> {
-    let utf8 = String::from_utf8(raw).map_err(Error::DecodingUtf8)?;
+fn to_text_and_headers(text: String, meta: &serde_json::Value) -> Result<TextAndHeaders> {
     let headers: Headers = serde_json::from_value(meta.clone()).map_err(|why| {
         Error::Deserializing(why, "reading headers from cache. Try clearing the cache.")
     })?;
-    Ok((utf8, headers))
+    Ok((text, headers))
 }

src/cache/tests.rs

@@ -9,25 +9,24 @@ lazy_static! {
     static ref TTL: Duration = Duration::minutes(1);
 }
 
-fn print_cache_list(header: &'static str) {
+fn print_cache_list(header: &'static str) -> Result<()> {
     println!("\n+--- Cache {} ---", header);
-    wrapper::list_cache()
-        .filter_map(|res| res.ok())
-        .for_each(|meta| {
-            let age_ms = meta.time;
-            let cache_age = chrono::Utc.timestamp((age_ms / 1000) as i64, (age_ms % 1000) as u32);
-            eprintln!(
-                "| - {}\n|   SIZE: {}\n|   AGE: {}",
-                meta.key, meta.size, cache_age
-            )
-        });
+    CACHE.list()?.iter().for_each(|meta| {
+        let age_ms = meta.time;
+        let cache_age = chrono::Utc.timestamp((age_ms / 1000) as i64, (age_ms % 1000) as u32);
+        eprintln!(
+            "| - {}\n|   SIZE: {}\n|   AGE: {}",
+            meta.key, meta.size, cache_age
+        )
+    });
     println!("+{}", "-".repeat(header.len() + 14));
+    Ok(())
 }
 
 #[test]
 fn test_cache_is_empty() {
-    let read = try_load_cache("test cache entry", Duration::max_value()).unwrap();
-    print_cache_list("Cache");
+    let read = try_load_cache(&*CACHE, "test cache entry", Duration::max_value()).unwrap();
+    print_cache_list("Cache").unwrap();
     assert_eq!(read, CacheResult::Miss);
 }
 
@@ -35,15 +34,15 @@ fn test_cache_is_empty() {
 fn basic_caching() {
     let url = "http://invalid.local/test";
     // Cache is empty
-    let val = try_load_cache(url, Duration::max_value()).unwrap();
-    print_cache_list("After first read");
+    let val = try_load_cache(&*CACHE, url, Duration::max_value()).unwrap();
+    print_cache_list("After first read").unwrap();
     assert_eq!(val, CacheResult::Miss);
     // Populate the cache with the first request
-    let val = fetch(url, *TTL, |txt, _| Ok(txt)).unwrap();
+    let val = CACHE.fetch(url, *TTL, |txt, _| Ok(txt)).unwrap();
     assert_eq!(val, "It works",);
     // The cache should now be hit
-    let val = try_load_cache(url, Duration::max_value()).unwrap();
-    print_cache_list("After second read");
+    let val = try_load_cache(&*CACHE, url, Duration::max_value()).unwrap();
+    print_cache_list("After second read").unwrap();
     assert_eq!(
         val,
         CacheResult::Hit((
@@ -58,6 +57,6 @@ fn basic_caching() {
     );
     // Let's fake a stale entry
     thread::sleep(std::time::Duration::from_secs(1));
-    let val = try_load_cache(url, Duration::zero()).unwrap();
+    let val = try_load_cache(&*CACHE, url, Duration::zero()).unwrap();
     assert!(matches!(val, CacheResult::Stale(_, _)));
 }

src/cache/wrapper.rs

@@ -1,66 +0,0 @@
-//! Wrapper for [`cacache`] and [`reqwest`] methods
-//!
-//! To make testing easier.
-use cacache::Metadata;
-use lazy_static::lazy_static;
-use tracing::info;
-
-use std::{io::Write, path::Path};
-
-use super::Headers;
-
-use crate::error::{Error, Result};
-
-pub fn write_cache(headers: &Headers, url: &str, text: &str) -> Result<()> {
-    let header_serialized = serde_json::to_value(headers.clone())
-        .map_err(|why| Error::Serializing(why, "writing headers to cache"))?;
-    let mut writer = cacache::WriteOpts::new()
-        .metadata(header_serialized)
-        .open_sync(cache(), url)
-        .map_err(|why| Error::Cache(why, "opening for write"))?;
-    writer
-        .write_all(text.as_bytes())
-        .map_err(|why| Error::Io(why, "writing value"))?;
-    writer
-        .commit()
-        .map_err(|why| Error::Cache(why, "commiting write"))?;
-    info!("Updated cache for {:?}", url);
-    Ok(())
-}
-
-pub fn read_cache(meta: &Metadata) -> Result<Vec<u8>> {
-    cacache::read_hash_sync(cache(), &meta.integrity)
-        .map_err(|why| Error::Cache(why, "reading value"))
-}
-
-pub fn read_cache_meta(url: &str) -> Result<Option<Metadata>> {
-    cacache::metadata_sync(cache(), url).map_err(|why| Error::Cache(why, "reading metadata"))
-}
-
-pub fn clear_cache() -> Result<()> {
-    cacache::clear_sync(cache()).map_err(|why| Error::Cache(why, "clearing"))
-}
-
-#[cfg(test)]
-pub fn list_cache() -> impl Iterator<Item = cacache::Result<Metadata>> {
-    cacache::list_sync(cache())
-}
-
-#[cfg(not(test))]
-fn cache() -> &'static Path {
-    use std::path::PathBuf;
-    lazy_static! {
-        /// Path to the cache.
-        static ref CACHE: PathBuf = crate::DIR.cache_dir().into();
-    }
-    &*CACHE
-}
-
-#[cfg(test)]
-fn cache() -> &'static Path {
-    lazy_static! {
-        static ref CACHE: temp_dir::TempDir =
-            temp_dir::TempDir::new().expect("Failed to create test cache dir");
-    }
-    CACHE.path()
-}

src/canteen/mod.rs

@@ -10,7 +10,7 @@ mod de;
 mod ser;
 
 use crate::{
-    cache::{fetch_json, Fetchable},
+    cache::{Cache, Fetchable, CACHE},
     config::{
         args::{CloseCommand, Command, GeoCommand},
         CONF,
@@ -63,7 +63,7 @@ pub struct Day {
 impl Meta {
     pub fn fetch(id: CanteenId) -> Result<Self> {
         let url = format!("{}/canteens/{}", OPEN_MENSA_API, id);
-        fetch_json(url, *TTL_CANTEENS)
+        CACHE.fetch_json(url, *TTL_CANTEENS)
     }
 }
 

src/geoip.rs

@@ -5,7 +5,7 @@ use lazy_static::lazy_static;
 use serde::Deserialize;
 
 use crate::{
-    cache::fetch_json,
+    cache::{Cache, CACHE},
     config::{
         args::{CloseCommand, Command},
         CONF,
@@ -56,5 +56,5 @@ pub fn infer() -> Result<(f32, f32)> {
 /// Fetch geoip for current ip.
 fn fetch_geoip() -> Result<LatLong> {
     let url = "https://api.geoip.rs";
-    fetch_json(url, *TTL_GEOIP)
+    CACHE.fetch_json(url, *TTL_GEOIP)
 }

src/main.rs

@@ -63,6 +63,7 @@
 //! - `$HOME/Library/Application Support/mensa/config.toml` on **macOS**,
 //! - `{FOLDERID_RoamingAppData}\mensa\config.toml` on **Windows**
 
+use cache::Cache;
 use chrono::Duration;
 use directories_next::ProjectDirs;
 use lazy_static::lazy_static;
@@ -139,6 +140,7 @@ mod tag;
 // mod tests;
 
 use crate::{
+    cache::CACHE,
     canteen::Canteen,
     config::{args::Command, CONF},
     error::{Error, Result, ResultExt},
@@ -169,7 +171,7 @@ fn real_main() -> Result<()> {
     tracing_subscriber::fmt::init();
     // Clear cache if requested
     if CONF.args.clear_cache {
-        cache::clear()?;
+        CACHE.clear()?;
     }
     // Match over the user requested command
     match CONF.cmd() {

src/pagination.rs

@@ -9,7 +9,7 @@ use serde::de::DeserializeOwned;
 use std::marker::PhantomData;
 
 use crate::{
-    cache,
+    cache::{Cache, CACHE},
     error::{Error, Result},
 };
 
@@ -75,7 +75,7 @@ where
     fn next(&mut self) -> Option<Self::Item> {
         // This will yield until no next_page is available
         let curr_page = self.next_page.take()?;
-        let res = cache::fetch(curr_page, self.ttl, |text, headers| {
+        let res = CACHE.fetch(curr_page, self.ttl, |text, headers| {
             let val = serde_json::from_str::<Vec<_>>(&text)
                 .map_err(|why| Error::Deserializing(why, "fetching json in pagination iterator"))?;
             Ok((val, headers.this_page, headers.next_page, headers.last_page))