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// Rust Standard Library Imports. use std::fmt::{self, Display}; // Module declarations. pub mod constants; pub mod util; /// Re-exports. pub use util::command_prelude; pub use util::errors::{Error, Result}; /// Primary structure used to generate imgix URLs. /// /// An *imgix* URL is comprised of four components: /// /// * scheme - the scheme being used (https by default). /// * domain - the domain, i.e. example.domain.net. /// * path - the path to the image file. /// * query - the query string constructed from `params`. /// /// ```text /// domain /// ┌──────┴──────┐ /// https://www.example.com/image/path.png/?w=320&h=640 /// └─┬─┘ └──────┬───────┘ └────┬────┘ /// scheme path params /// ``` /// /// This structure is meant to be a crate primitive that /// crate users _and_ contributors can use to build on. This /// is part of the reason why many of the building functions /// can panic. They panic to try to ensure invalid urls are /// never constructed. This is to provide higher-level structures /// certain guarantees about the representation of a `Url`. pub struct Url { /// The scheme component of a URL, i.e. https, http, etc. scheme: Scheme, /// The domain, i.e. example.domain.net domain: String, /// The library generating the `Url`. If you want to turn on /// analytics, call `ix()` and the library version will be set /// to the value of `"ixlib=rust-0.1.0"`. It helps us help our /// users, but it's _your choice_ to _opt in_. Your code, /// Your choice. What you see is what you get (WYSIWYG). lib: String, /// The path to the image file, e.g. "ixlib=rust-0.1.0" path: Option<String>, /// The parameters used to construct the query string. /// /// This structure is a _key-value list_ and been chosen over HashMap, /// BTreeMap, and BTreeSet for the following reasons: /// /// * to give users __flexibility__, by accepting a range of inputs /// * to seek __consistency__, by ordering parameters in the order /// they were defined, (WYSIWYG) /// * to give users control /// /// The query-string is built up during a single iterative pass over this /// key-value list, visiting each key-value pair in the order the user /// has specified. Therefore, the order in which parameters are listed /// is the same order they will appear in the generated `Url`'s query /// string. params: Vec<(&'static str, &'static str)>, /// Optional signing token used to sign URLs. token: Option<String>, } impl Default for Url { /// By default a URL is created with its `scheme` set /// to `Scheme::Https` and the `lib` value set to the version /// specified in this library's Cargo.toml fn default() -> Self { Url { scheme: Scheme::Https, domain: "".to_owned(), lib: "".to_owned(), params: vec![], path: None, token: None, } } } impl Url { /// Construct a new `Url` given a domain. /// /// # Panics /// /// This constructor will fail if the `domain` is an empty string. pub fn new(domain: &'static str) -> Self { assert!(!domain.is_empty()); Url { domain: String::from(domain), ..Default::default() } } /// Set the domain value (i.e. "example.domain.net"). /// /// # Panics /// /// This method panics if passed an empty string. pub fn domain(mut self, d: &str) -> Self { assert!(!d.is_empty()); self.domain = String::from(d); self } /// Set the path value to the image file (i.e. 'image/path.png'). /// /// # Panics /// /// This method panics if passed an empty string. pub fn path(mut self, p: &str) -> Self { assert!(!p.is_empty()); self.path = Some(String::from(p)); self } /// Set an arbitrary key-value parameter (i.e. k='w', v='100' /// or k='fit', v='crop'). /// /// # Examples /// ``` /// use imgix::Url; /// let url = Url::new("example.domain.net").param("w", "320").path("test").lib(""); /// let right = "https://example.domain.net/test?w=320"; /// assert_eq!(url.join(), "https://example.domain.net/test?w=320") /// ``` /// /// # Panics /// /// This method panics if any key `k` or any value `v` is an empty string, /// where `k` and `v` represent string literals. pub fn param(mut self, k: &'static str, v: &'static str) -> Self { assert!(!k.is_empty()); assert!(!v.is_empty()); self.params.push((k, v)); self } /// Set an arbitrary number of key-value parameters. /// /// # Examples /// ``` /// use imgix::Url; /// /// let url = Url::new("example.domain.net") /// .path("test").lib("") /// .params(&[("w", "320"), /// ("h", "640"), /// ("fit", "crop")]); /// /// let right = "https://example.domain.net/test?w=320&h=640&fit=crop"; /// assert_eq!(url.join(), right); /// ``` /// /// # Panics /// /// This method panics if any key `k` or any value `v` is an empty string. pub fn params(mut self, p: &[(&'static str, &'static str)]) -> Self { for (k, v) in p.iter() { assert!(!k.is_empty()); assert!(!v.is_empty()); self.params.push((k, v)); } self } /// Set the library version explicitly, see `Url::ix()` for the /// implicit default. /// /// The `Url`'s `lib` value can be set to any `String` by passing /// the desired string literal. If the `lib` is a valid ix-lib /// parameter if will be considered on the server. However, if /// an invalid lib-parameter is passed, e.g. "rust-is-cool", it /// will be ignored (appreciated ;) but ignored). /// /// Examples /// ``` /// use imgix::{constants::lib_version, Scheme, Url}; /// /// const DOMAIN: &str = "example.domain.net"; /// const PATH: &str = "image.png"; /// /// let url = Url::new(DOMAIN) /// .lib(&lib_version()) /// .path("image.png"); /// /// let right = format!( /// "{scheme}://{domain}/{path}?{lib}", /// scheme = Scheme::Https, /// domain = DOMAIN, /// path = PATH, /// lib = lib_version() /// ); /// /// assert_eq!(url.join(), right); /// /// let url = url.lib("rust-is-cool"); /// assert_ne!(url.join(), right); /// ``` pub fn lib(mut self, l: &str) -> Self { self.lib = String::from(l); self } /// Set the signing token. /// TODO: Test token post md5 implementation. pub fn token(mut self, t: &str) -> Self { self.token = Some(String::from(t)); self } // Set the `scheme` value (i.e. `Scheme::Https`). pub fn scheme(mut self, s: Scheme) -> Self { self.scheme = s; self } // Set the library version to this crate's current `lib_version()`. // In the official imgix docs the `ixlib` parameter is used for // _diagnostic purposes_. It helps us help our users and customers, // but it's _your choice_ to _opt in_. Your code, Your choice. // What you see is what you get (WYSIWYG). pub fn ix(mut self) -> Self { self.lib = constants::lib_version(); self } /// Join the components of a `Url` (i.e. `scheme` + `domain` + `path` + /// `params`) where the resulting string has the following form: /// /// {scheme}://{domain}/{path}?{lib}{query} /// /// This function will only `join` the components of a `Url` if a `path` /// has been specified. /// /// # Panics /// /// This function will panic if the image `path` has not been specified. /// (i.e. if the `path` is `None`). This is to ensure that a `Url` is /// joined if it is in a _valid_ state. pub fn join(&self) -> String { // Join this url, only-if a `path` has been specified. match self.path { Some(ref path) => { let query = Self::join_params(&self.params); // If we make it here then the following is true: // * a path has been assigned and is not `None` // * a query string was generated successfully and // is either empty or non-empty. match (&self.lib.is_empty(), &query.is_empty()) { // All present, no empty fields, construct full url. (false, false) => format!( "{scheme}://{domain}/{path}?{lib}&{query}", scheme = self.scheme, domain = self.domain, path = path, lib = self.lib, query = query, ), // Query string is empty, but lib is non-empty. (false, true) => format!( "{scheme}://{domain}/{path}?{lib}", scheme = self.scheme, domain = self.domain, lib = self.lib, path = path, ), // Lib is empty, but query is non-empty. (true, false) => format!( "{scheme}://{domain}/{path}?{query}", scheme = self.scheme, domain = self.domain, path = path, query = query ), // Both lib and query strings are empty. (true, true) => format!( "{scheme}://{domain}/{path}", scheme = self.scheme, domain = self.domain, path = path, ), } } None => { panic!("failed: cannot `Url::join` when `path` is `None`."); } } } /// Join a list of key-value parameter pairs. /// /// # Examples /// /// # Panics /// /// This function panics if any key `k` or any value `v` is an empty string. pub fn join_params(p: &[(&'static str, &'static str)]) -> String { let mut result = String::new(); // I the parameter list is empty, do no work. if p.is_empty() { return result; } // Otherwise, construct the result by appending parameters one after another // (i.e. {key}={value}{"&" | ""}). // The result has the form: k0=v0&k1=v1&k2=v2 let mut it = 1usize; let end = p.len(); for (k, v) in p.iter() { assert!(!k.is_empty()); assert!(!v.is_empty()); result.push_str(k); result.push('='); result.push_str(v); // Avoid pushing a trailing '&' if there are no more parameter pairs. if it < end { result.push('&'); } it += 1; } return result; } } /// Primary value for expressing which scheme a url uses. /// /// This is an enum to define and enforce the crate semantics of what /// it _means_ for a url to be valid for our use-case. A url can be /// in one of two _states_: it either uses https or it uses http. While /// this can be achieved by toggling https on and off via a boolean value, /// a boolean value weakens the semantics and constrains the range of possible /// schemes that can be used in the future. /// /// Using `Scheme::Https` is also more explicit than saying `url.https(true)`, /// it also has the added benefit of being _discoverable_. When usage is /// `url.scheme(Scheme::...)`, the range of possible schemes can be discovered /// by IDE code completion tools. #[derive(Debug, PartialEq)] pub enum Scheme { Https, Http, } impl Display for Scheme { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { match self { Scheme::Https => write!(f, "{}", "https"), Scheme::Http => write!(f, "{}", "http"), } } } #[cfg(test)] mod test { use super::*; const HTTPS: &str = "https"; const HTTP: &str = "http"; const DOMAIN: &str = "test.domain.com"; const DOMAIN2: &str = "test.domain2.com"; const PNG_PATH: &str = "images/test-image.png"; const JPG_PATH: &str = "images/test-image.jpg"; const BASIC_PARAMS: &[(&str, &str)] = &[("w", "640"), ("h", "720"), ("fit", "crop")]; #[test] fn test_join_params() { let left = Url::join_params(&[("w", "300")]); assert_eq!(left, String::from("w=300")); let left = Url::join_params(&[("w", "300"), ("h", "600")]); assert_eq!(left, String::from("w=300&h=600")); let left = Url::join_params(&[("w", "300"), ("h", "600"), ("fit", "crop")]); assert_eq!(left, String::from("w=300&h=600&fit=crop")); } #[test] fn test_default_url() { // Test the default representation of a `Url`. let default = Url::default(); assert_eq!(default.scheme, Scheme::Https); assert_eq!(default.domain, "".to_owned()); assert_eq!(default.lib, "".to_owned()); assert_eq!(default.params, vec![]); assert_eq!(default.path, None); assert_eq!(default.token, None); } #[test] fn test_url_new() { let url = Url::new(DOMAIN); assert_eq!(url.domain, DOMAIN); let url = Url::new(DOMAIN2); assert_ne!(url.domain, "".to_owned()); } #[test] fn test_url_domain() { let url = Url::new(DOMAIN); assert_ne!(url.domain, DOMAIN2); let url = url.domain(DOMAIN2); assert_eq!(url.domain, DOMAIN2); } #[test] #[should_panic] fn test_construct_empty_domain() { let _ = Url::new(""); } #[test] #[should_panic] fn test_assign_empty_domain() { let _ = Url::default().domain(""); } #[test] fn test_assign_path() { let url = Url::default().path(PNG_PATH); assert_eq!(url.path, Some(PNG_PATH.to_owned())); } #[test] #[should_panic] fn test_assign_empty_path() { let _ = Url::default().path(""); } #[test] fn test_assign_param() { const K: &str = "w"; const V: &str = "320"; let url = Url::default().param(K, V); for (k, v) in url.params.iter() { assert_eq!(*k, K); assert_eq!(*v, V); } } #[test] #[should_panic] fn test_assign_empty_key_param() { const V: &str = "320"; const KE: &str = ""; let _ = Url::default().param(KE, V); } #[test] #[should_panic] fn test_assign_empty_value_param() { const VE: &str = ""; const K: &str = "w"; let _ = Url::default().param(K, VE); } #[test] fn test_assign_params() { let url = Url::default().params(BASIC_PARAMS); // Test params assigned correctly. for (left, right) in url.params.iter().zip(BASIC_PARAMS.iter()) { assert_eq!(left.0, right.0); assert_eq!(left.1, right.1); } } #[test] #[should_panic] fn test_assign_params_mismatch() { // This assertion is necessary for this test's validity. // If the slices were of length 3 and length 4, and only differed // in the 4th position, we would not know it as `zip` only zips // pairs––the 4th item is discarded (only 3 pairs would be made). assert_eq!(BASIC_PARAMS.len(), HAS_AR.len()); const HAS_AR: &[(&str, &str)] = &[("w", "640"), ("h", "720"), ("ar", "4:3")]; let url = Url::default().params(BASIC_PARAMS); // Test params assigned correctly. for (left, right) in url.params.iter().zip(HAS_AR.iter()) { // This test is designed to fail on the third iteration. assert_eq!(left.0, right.0); assert_eq!(left.1, right.1); } } #[test] fn test_url_png_src() { // Test a `Url` is constructed correctly. let right = format!( "{scheme}://{domain}/{path}", scheme = HTTPS, domain = DOMAIN, path = PNG_PATH, ); let url = Url::new(DOMAIN).path(PNG_PATH); // Test all fields. assert_eq!(url.scheme, Scheme::Https); assert_eq!(url.domain, DOMAIN); assert_eq!(url.lib, "".to_owned()); assert_eq!(url.path, Some(String::from(PNG_PATH))); assert!(url.params.is_empty()); assert!(url.token.is_none()); assert_eq!(url.join(), right); } #[test] fn test_url_jpg_src() { // Test a `Url` is constructed correctly. let right = format!( "{scheme}://{domain}/{path}", scheme = HTTP, domain = DOMAIN, path = JPG_PATH, ); let url = Url::new(DOMAIN).path(JPG_PATH).scheme(Scheme::Http); // Test all fields. assert_eq!(url.scheme, Scheme::Http); assert_eq!(url.domain, DOMAIN); assert_eq!(url.lib, "".to_owned()); assert_eq!(url.path, Some(String::from(JPG_PATH))); assert!(url.params.is_empty()); assert_eq!(url.join(), right); } }