From 72de4e228394826e7d90e24f5794242523389d10 Mon Sep 17 00:00:00 2001
From: Esteban Borai <estebanborai@gmail.com>
Date: Fri, 9 Oct 2020 20:24:22 -0300
Subject: [PATCH 1/4] refactor: handlers and routes

---
 CHANGELOG.md                                  |  9 ++
 Cargo.lock                                    |  2 +-
 Cargo.toml                                    |  2 +-
 README.md                                     |  1 -
 .../{static_fs => file_explorer}/handler.rs   | 44 +++++-----
 .../{static_fs => file_explorer}/html/mod.rs  |  0
 .../html/static/index.html                    |  0
 .../html/static/style.css                     |  0
 .../{static_fs => file_explorer}/mod.rs       |  0
 src/handler/main_handler.rs                   | 17 ++++
 src/handler/mod.rs                            |  6 +-
 src/main.rs                                   | 87 -------------------
 src/{server.rs => server/http.rs}             | 14 ++-
 src/server/mod.rs                             |  3 +
 14 files changed, 65 insertions(+), 120 deletions(-)
 create mode 100644 CHANGELOG.md
 rename src/handler/{static_fs => file_explorer}/handler.rs (59%)
 rename src/handler/{static_fs => file_explorer}/html/mod.rs (100%)
 rename src/handler/{static_fs => file_explorer}/html/static/index.html (100%)
 rename src/handler/{static_fs => file_explorer}/html/static/style.css (100%)
 rename src/handler/{static_fs => file_explorer}/mod.rs (100%)
 create mode 100644 src/handler/main_handler.rs
 rename src/{server.rs => server/http.rs} (72%)
 create mode 100644 src/server/mod.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 00000000..5056567c
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,9 @@
+# Changes
+
+## v0.0.9
+
+### Added
+
+* [CLI](https://github.com/EstebanBorai/http-server/commit/f7ea5b278e8b46c322d82c324c7f263ecae3914b)
+* [Config Shape](https://github.com/EstebanBorai/http-server/commit/49e4cd73ddc4401bf684ad70875b075bb35caf5a)
+* [HTTP server with File Explorer](https://github.com/EstebanBorai/http-server/commit/7aa59495dab51c52a0a79b75c185b3b74dda5be1)
diff --git a/Cargo.lock b/Cargo.lock
index 4dc98492..364a78b1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -89,7 +89,7 @@ dependencies = [
 
 [[package]]
 name = "http-server"
-version = "0.0.9"
+version = "0.0.10"
 dependencies = [
  "ascii",
  "clap",
diff --git a/Cargo.toml b/Cargo.toml
index 514de23e..3dcf3c72 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "http-server"
-version = "0.0.9"
+version = "0.0.10"
 authors = ["Esteban Borai <estebanborai@gmail.com>"]
 edition = "2018"
 license = "MIT"
diff --git a/README.md b/README.md
index 6b47f6da..4e0463de 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,6 @@
 <div align="center">
 
   [![Crates.io](https://img.shields.io/crates/v/http-server.svg)](https://crates.io/crates/http-server)
-  [![Documentation](https://docs.rs/http-server/badge.svg)](https://docs.rs/http-server)
   ![Build](https://github.com/EstebanBorai/http-server/workflows/build/badge.svg)
   ![Lint](https://github.com/EstebanBorai/http-server/workflows/clippy/fmt/badge.svg)
   ![Tests](https://github.com/EstebanBorai/http-server/workflows/tests/badge.svg)
diff --git a/src/handler/static_fs/handler.rs b/src/handler/file_explorer/handler.rs
similarity index 59%
rename from src/handler/static_fs/handler.rs
rename to src/handler/file_explorer/handler.rs
index bff30411..bedb0fb5 100644
--- a/src/handler/static_fs/handler.rs
+++ b/src/handler/file_explorer/handler.rs
@@ -2,7 +2,7 @@ use crate::file_explorer::FileExplorer;
 use crate::handler::build_html;
 use ascii::AsciiString;
 use std::fs::{read_dir, File};
-use tiny_http::{Request, Response};
+use tiny_http::{Request, Response, ResponseBox};
 
 /// Creates a path by merging the URL params and the `root_dir`.
 /// Then reads the file system entries in the resulting path.
@@ -11,7 +11,7 @@ use tiny_http::{Request, Response};
 /// and responds with an HTML with the entry listing.
 ///
 /// Otherwise retrieves the provided file.
-pub fn static_fs(request: Request, file_explorer: &FileExplorer) {
+pub fn file_explorer(request: Request, file_explorer: &FileExplorer) -> (Request, ResponseBox) {
     match file_explorer.read(request.url().as_ref()) {
         Ok(entry) => {
             if entry.is_file {
@@ -20,12 +20,16 @@ pub fn static_fs(request: Request, file_explorer: &FileExplorer) {
                     .to_string();
                 let mime_type = AsciiString::from_ascii(mime_type.as_bytes()).unwrap();
                 let file = File::open(entry.path).unwrap();
-                let response = Response::from_file(file).with_header(tiny_http::Header {
-                    field: "Content-Type".parse().unwrap(),
-                    value: mime_type,
-                });
 
-                request.respond(response).unwrap();
+                (
+                    request,
+                    Response::from_file(file)
+                        .with_header(tiny_http::Header {
+                            field: "Content-Type".parse().unwrap(),
+                            value: mime_type,
+                        })
+                        .boxed(),
+                )
             } else {
                 let dirpath = entry.path.clone();
                 let dirpath = dirpath.to_str().unwrap();
@@ -40,21 +44,21 @@ pub fn static_fs(request: Request, file_explorer: &FileExplorer) {
                     entries,
                 );
                 let mime_type_value: AsciiString = AsciiString::from_ascii("text/html").unwrap();
+                let response = Response::from_string(html)
+                    .with_status_code(200)
+                    .with_header(tiny_http::Header {
+                        field: "Content-Type".parse().unwrap(),
+                        value: mime_type_value,
+                    });
 
-                request
-                    .respond(
-                        Response::from_string(html)
-                            .with_status_code(200)
-                            .with_header(tiny_http::Header {
-                                field: "Content-Type".parse().unwrap(),
-                                value: mime_type_value,
-                            }),
-                    )
-                    .unwrap()
+                (request, response.boxed())
             }
         }
-        Err(_) => request
-            .respond(Response::from_string("Not Found").with_status_code(404))
-            .unwrap(),
+        Err(_) => (
+            request,
+            Response::from_string("Not Found")
+                .with_status_code(404)
+                .boxed(),
+        ),
     }
 }
diff --git a/src/handler/static_fs/html/mod.rs b/src/handler/file_explorer/html/mod.rs
similarity index 100%
rename from src/handler/static_fs/html/mod.rs
rename to src/handler/file_explorer/html/mod.rs
diff --git a/src/handler/static_fs/html/static/index.html b/src/handler/file_explorer/html/static/index.html
similarity index 100%
rename from src/handler/static_fs/html/static/index.html
rename to src/handler/file_explorer/html/static/index.html
diff --git a/src/handler/static_fs/html/static/style.css b/src/handler/file_explorer/html/static/style.css
similarity index 100%
rename from src/handler/static_fs/html/static/style.css
rename to src/handler/file_explorer/html/static/style.css
diff --git a/src/handler/static_fs/mod.rs b/src/handler/file_explorer/mod.rs
similarity index 100%
rename from src/handler/static_fs/mod.rs
rename to src/handler/file_explorer/mod.rs
diff --git a/src/handler/main_handler.rs b/src/handler/main_handler.rs
new file mode 100644
index 00000000..31f84058
--- /dev/null
+++ b/src/handler/main_handler.rs
@@ -0,0 +1,17 @@
+use crate::file_explorer::FileExplorer;
+use crate::handler::file_explorer;
+use tiny_http::{Request, Response, ResponseBox};
+
+/// The main handler acts like a router for every supported method.
+/// If a method is not supported then responds with `Method Not Allowed 405`
+pub fn main_handler(req: Request, fexplorer: &FileExplorer) -> (Request, ResponseBox) {
+    match req.method().to_string().to_lowercase().as_str() {
+        "get" => file_explorer(req, fexplorer),
+        _ => (
+            req,
+            Response::from_string("Method Not Allowed")
+                .with_status_code(405)
+                .boxed(),
+        ),
+    }
+}
diff --git a/src/handler/mod.rs b/src/handler/mod.rs
index 29323f27..0132536c 100644
--- a/src/handler/mod.rs
+++ b/src/handler/mod.rs
@@ -1,3 +1,5 @@
-mod static_fs;
+mod file_explorer;
+mod main_handler;
 
-pub use static_fs::*;
+pub use file_explorer::*;
+pub use main_handler::*;
diff --git a/src/main.rs b/src/main.rs
index c0c5cc35..04e571e2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,90 +1,3 @@
-//! <div>
-//!   <div align="center" style="display: block; text-align: center;">
-//!     <img src="https://raw.githubusercontent.com/EstebanBorai/http-server/main/docs/http-logo.png" height="120" width="200" />
-//!   </div>
-//!   <h1 align="center">http-server</h1>
-//!   <h4 align="center">Command-line HTTP Server</h4>
-//! </div>
-//!
-//! <div align="center">
-//!
-//!   [![Crates.io](https://img.shields.io/crates/v/http-server.svg)](https://crates.io/crates/http-server)
-//!   [![Documentation](https://docs.rs/http-server/badge.svg)](https://docs.rs/http-server)
-//!   ![Build](https://github.com/EstebanBorai/http-server/workflows/build/badge.svg)
-//!   ![Lint](https://github.com/EstebanBorai/http-server/workflows/clippy/fmt/badge.svg)
-//!   ![Tests](https://github.com/EstebanBorai/http-server/workflows/tests/badge.svg)
-//!
-//! </div>
-//!
-//! ## Index
-//!
-//! - [Installation](#installation)
-//! - [Usage](#usage)
-//!     - [Flags](#flags)
-//!     - [Options](#options)
-//! - [Contributing](#contributing)
-//! - [License](#license)
-//!     - [Contribution](#contribution)
-//!
-//! ## Installation
-//!
-//! ```bash
-//! cargo install http-server
-//! ```
-//!
-//! Check for the installation to be successful.
-//!
-//! ```bash
-//! http-server --help
-//! ```
-//!
-//! ## Usage
-//!
-//! ```
-//! http-server [FLAGS] [OPTIONS] [root_dir]
-//! ```
-//!
-//! ### Flags
-//!
-//! Flags are provided without any values. For example:
-//!
-//! ```
-//! http-server --help
-//! ```
-//!
-//! Name | Short | Long | Description
-//! --- | --- | --- | ---
-//! Help | `h` | `help` | Prints help information
-//! Version | `V` | `version` | Prints version information
-//!
-//! ### Options
-//!
-//! Options are provided with a value and also have default values. For example:
-//!
-//! ```
-//! http-server --address 127.0.0.1
-//! ```
-//!
-//! Name | Short | Long | Description | Default Value
-//! --- | --- | --- | --- | ---
-//! Address | `a` | `address` | Address to bind the server | `0.0.0.0`
-//! Port | `p` | `port` | Port to bind the server | `7878`
-//!
-//! ## Contributing
-//!
-//! Every contribution to this project is welcome. Feel free to open a pull request,
-//! an issue or just by starting this project.
-//!
-//! ## License
-//!
-//! Licensed under the MIT License
-//!
-//! ### Contribution
-//!
-//! Unless you explicitly state otherwise, any contribution intentionally submitted for
-//! inclusion in http-server by you, shall be dual licensed as above, without any additional
-//! terms or conditions.
-//!
 mod cli;
 mod config;
 mod file_explorer;
diff --git a/src/server.rs b/src/server/http.rs
similarity index 72%
rename from src/server.rs
rename to src/server/http.rs
index 3c9bac6a..ce0b0df9 100644
--- a/src/server.rs
+++ b/src/server/http.rs
@@ -1,9 +1,10 @@
 use crate::config::Config;
 use crate::file_explorer::FileExplorer;
-use crate::handler::static_fs;
+use crate::handler::main_handler;
 use std::net::SocketAddr;
-use tiny_http::{Response, Server, ServerConfig};
+use tiny_http::{Server, ServerConfig};
 
+/// HTTP Server instance
 pub struct HttpServer {
     pub server: tiny_http::Server,
     pub address: SocketAddr,
@@ -31,6 +32,7 @@ impl From<Config> for HttpServer {
 }
 
 impl HttpServer {
+    /// Binds the server to the specified address and listen for incomming requests
     pub fn serve(&self) {
         if self.must_log {
             println!(
@@ -40,12 +42,8 @@ impl HttpServer {
         }
 
         for request in self.server.incoming_requests() {
-            match request.method().as_str().to_lowercase().as_str() {
-                "get" => static_fs(request, &self.file_explorer),
-                _ => request
-                    .respond(Response::from_string("Method Not Allowed").with_status_code(405))
-                    .unwrap(),
-            }
+            let (req, res) = main_handler(request, &self.file_explorer);
+            req.respond(res).unwrap();
         }
     }
 }
diff --git a/src/server/mod.rs b/src/server/mod.rs
new file mode 100644
index 00000000..8e815309
--- /dev/null
+++ b/src/server/mod.rs
@@ -0,0 +1,3 @@
+mod http;
+
+pub use http::*;

From 54be7c0e2cf00d01962e4186f8952f5e5e7dc138 Mon Sep 17 00:00:00 2001
From: Esteban Borai <estebanborai@gmail.com>
Date: Wed, 14 Oct 2020 23:07:05 -0300
Subject: [PATCH 2/4] add: entity tag support

Implements an Entity Tag hash by obtaining the date created, the
date of the last modification and the size of the file.
---
 CHANGELOG.md                         |  6 ++++++
 src/config.rs                        |  2 --
 src/handler/file_explorer/handler.rs | 11 +++++++++--
 src/server/etag.rs                   | 17 +++++++++++++++++
 src/server/mod.rs                    |  2 ++
 5 files changed, 34 insertions(+), 4 deletions(-)
 create mode 100644 src/server/etag.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5056567c..7f36bcc9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changes
 
+## v0.0.10
+
+### Added
+
+* [Etag Support](https://github.com/EstebanBorai/http-server/commit/32dc9a2e6b32bb18906ef06d45c155731d91519e)
+
 ## v0.0.9
 
 ### Added
diff --git a/src/config.rs b/src/config.rs
index 63811990..d2e26630 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -28,8 +28,6 @@ impl From<App<'static, 'static>> for Config {
         };
 
         let silent = matches.is_present(SILENT.1);
-
-        // at this point the values provided to the config are validated by the CLI
         Self {
             address,
             port,
diff --git a/src/handler/file_explorer/handler.rs b/src/handler/file_explorer/handler.rs
index bedb0fb5..30e7543c 100644
--- a/src/handler/file_explorer/handler.rs
+++ b/src/handler/file_explorer/handler.rs
@@ -1,5 +1,6 @@
 use crate::file_explorer::FileExplorer;
 use crate::handler::build_html;
+use crate::server::make_entity_tag;
 use ascii::AsciiString;
 use std::fs::{read_dir, File};
 use tiny_http::{Request, Response, ResponseBox};
@@ -16,10 +17,12 @@ pub fn file_explorer(request: Request, file_explorer: &FileExplorer) -> (Request
         Ok(entry) => {
             if entry.is_file {
                 let mime_type = mime_guess::from_path(&entry.path)
-                    .first_or_octet_stream()
-                    .to_string();
+                .first_or_octet_stream()
+                .to_string();
                 let mime_type = AsciiString::from_ascii(mime_type.as_bytes()).unwrap();
                 let file = File::open(entry.path).unwrap();
+                let entity_tag = make_entity_tag(&file.metadata().unwrap());
+                let entity_tag = AsciiString::from_ascii(entity_tag).unwrap();
 
                 (
                     request,
@@ -28,6 +31,10 @@ pub fn file_explorer(request: Request, file_explorer: &FileExplorer) -> (Request
                             field: "Content-Type".parse().unwrap(),
                             value: mime_type,
                         })
+                        .with_header(tiny_http::Header {
+                            field: "Etag".parse().unwrap(),
+                            value: entity_tag
+                        })
                         .boxed(),
                 )
             } else {
diff --git a/src/server/etag.rs b/src/server/etag.rs
new file mode 100644
index 00000000..88abc545
--- /dev/null
+++ b/src/server/etag.rs
@@ -0,0 +1,17 @@
+use std::fs::Metadata;
+use std::time::SystemTime;
+use std::hash::{Hash, Hasher};
+use std::collections::hash_map::DefaultHasher;
+
+/// Creates an Entity Tag from a `File` `Metadata`
+pub fn make_entity_tag(meta: &Metadata) -> String {
+  let mut created_hasher = DefaultHasher::new();
+  let mut modified_hasher = DefaultHasher::new();
+  let mut size_hasher = DefaultHasher::new();
+
+  meta.len().hash(&mut size_hasher);
+  meta.created().unwrap_or(SystemTime::now()).hash(&mut created_hasher);
+  meta.modified().unwrap_or(SystemTime::now()).hash(&mut modified_hasher);
+
+  format!("{0:x}{1:x}{2:x}", created_hasher.finish(), modified_hasher.finish(), size_hasher.finish())
+}
diff --git a/src/server/mod.rs b/src/server/mod.rs
index 8e815309..61a62336 100644
--- a/src/server/mod.rs
+++ b/src/server/mod.rs
@@ -1,3 +1,5 @@
+mod etag;
 mod http;
 
+pub use etag::*;
 pub use http::*;

From 1a29ebaa99d54709948bc0fd4a90e49375282d7b Mon Sep 17 00:00:00 2001
From: Esteban Borai <estebanborai@gmail.com>
Date: Fri, 16 Oct 2020 23:26:49 -0300
Subject: [PATCH 3/4] wip: entity tag weak

---
 src/error.rs                         | 14 +++++
 src/handler/file_explorer/handler.rs | 14 +++--
 src/main.rs                          |  1 +
 src/server/etag.rs                   | 17 ------
 src/server/header/etag.rs            | 80 ++++++++++++++++++++++++++++
 src/server/header/http_header.rs     | 19 +++++++
 src/server/header/mod.rs             |  5 ++
 src/server/mod.rs                    |  4 +-
 8 files changed, 127 insertions(+), 27 deletions(-)
 create mode 100644 src/error.rs
 delete mode 100644 src/server/etag.rs
 create mode 100644 src/server/header/etag.rs
 create mode 100644 src/server/header/http_header.rs
 create mode 100644 src/server/header/mod.rs

diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 00000000..b5354a65
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,14 @@
+#[derive(Debug)]
+pub struct HttpError {
+  pub status_code: u16,
+  pub message: String,
+}
+
+impl HttpError {
+  pub fn new(status_code: u16, message: &str) -> Self {
+    Self {
+      status_code,
+      message: message.to_string(),
+    }
+  }
+}
diff --git a/src/handler/file_explorer/handler.rs b/src/handler/file_explorer/handler.rs
index 30e7543c..cee464c2 100644
--- a/src/handler/file_explorer/handler.rs
+++ b/src/handler/file_explorer/handler.rs
@@ -1,9 +1,9 @@
 use crate::file_explorer::FileExplorer;
 use crate::handler::build_html;
-use crate::server::make_entity_tag;
+use crate::server::{ETag, HttpHeader};
 use ascii::AsciiString;
 use std::fs::{read_dir, File};
-use tiny_http::{Request, Response, ResponseBox};
+use tiny_http::{Header, Request, Response, ResponseBox};
 
 /// Creates a path by merging the URL params and the `root_dir`.
 /// Then reads the file system entries in the resulting path.
@@ -21,8 +21,9 @@ pub fn file_explorer(request: Request, file_explorer: &FileExplorer) -> (Request
                 .to_string();
                 let mime_type = AsciiString::from_ascii(mime_type.as_bytes()).unwrap();
                 let file = File::open(entry.path).unwrap();
-                let entity_tag = make_entity_tag(&file.metadata().unwrap());
-                let entity_tag = AsciiString::from_ascii(entity_tag).unwrap();
+                let entity_tag = ETag::from_metadata(&file.metadata().unwrap()).unwrap();
+                let entity_tag: HttpHeader = entity_tag.into();
+                let entity_tag: Header = entity_tag.into();
 
                 (
                     request,
@@ -31,10 +32,7 @@ pub fn file_explorer(request: Request, file_explorer: &FileExplorer) -> (Request
                             field: "Content-Type".parse().unwrap(),
                             value: mime_type,
                         })
-                        .with_header(tiny_http::Header {
-                            field: "Etag".parse().unwrap(),
-                            value: entity_tag
-                        })
+                        .with_header(entity_tag)
                         .boxed(),
                 )
             } else {
diff --git a/src/main.rs b/src/main.rs
index 04e571e2..894856f3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 mod cli;
 mod config;
+mod error;
 mod file_explorer;
 mod handler;
 mod server;
diff --git a/src/server/etag.rs b/src/server/etag.rs
deleted file mode 100644
index 88abc545..00000000
--- a/src/server/etag.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-use std::fs::Metadata;
-use std::time::SystemTime;
-use std::hash::{Hash, Hasher};
-use std::collections::hash_map::DefaultHasher;
-
-/// Creates an Entity Tag from a `File` `Metadata`
-pub fn make_entity_tag(meta: &Metadata) -> String {
-  let mut created_hasher = DefaultHasher::new();
-  let mut modified_hasher = DefaultHasher::new();
-  let mut size_hasher = DefaultHasher::new();
-
-  meta.len().hash(&mut size_hasher);
-  meta.created().unwrap_or(SystemTime::now()).hash(&mut created_hasher);
-  meta.modified().unwrap_or(SystemTime::now()).hash(&mut modified_hasher);
-
-  format!("{0:x}{1:x}{2:x}", created_hasher.finish(), modified_hasher.finish(), size_hasher.finish())
-}
diff --git a/src/server/header/etag.rs b/src/server/header/etag.rs
new file mode 100644
index 00000000..652d9edd
--- /dev/null
+++ b/src/server/header/etag.rs
@@ -0,0 +1,80 @@
+use crate::server::header::HttpHeader;
+use std::fs::Metadata;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+/// The ETag response-header field provides the current value of the entity tag
+/// for the requested variant. The headers used with entity tags are described in
+/// sections 14.24, 14.26 and 14.44. The entity tag MAY be used for comparison
+/// with other entities from the same resource (see section 13.3.3).
+///
+/// # Anatomy
+///
+/// The value of an ETag must follow the ABNF form:
+///
+/// ```
+/// entity-tag = [ weak ] opaque-tag
+///
+/// weak           = "W/"
+/// opaque-tag     = quoted-string
+/// ```
+///
+/// Reference: [US-ASCII Coded Character Set](https://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2)
+///
+/// The anatomy of an ETag may vary based on its type.
+/// An ETag could be either _weak_ or _strong_.
+///
+/// A _weak_ ETag is denoted by the prefix `W/`:
+///
+/// ```
+/// ETag: W/"557b5a3d3eca3aa493d35e47e94c94a2"
+/// ```
+///
+/// In the other hand a _strong_ Etag have no prefix.
+///
+/// # References
+///
+/// * [W3 RFC2616 - Sec 2](https://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2)
+/// * [W3 RFC2616 - Sec 14](https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19)
+pub struct ETag {
+  value: String,
+}
+
+impl ETag {
+  /// Creates an **strong** entity tag from the
+  /// provided metadata
+  pub fn from_metadata(meta: &Metadata) -> Result<Self, ()> {
+    let time_created = meta.created().unwrap_or(SystemTime::now())
+      .duration_since(UNIX_EPOCH)
+      .unwrap();
+
+    let time_modified = meta.modified().unwrap_or(SystemTime::now())
+      .duration_since(UNIX_EPOCH)
+      .unwrap();
+
+    let tag = format!("{:x}{:x}{:x}", time_created.subsec_millis(), time_modified.subsec_millis(), meta.len());
+
+    if ETag::is_valid_tag(&tag) {
+      return Ok(Self {
+        value: tag
+      })
+    }
+
+    Err(())
+  }
+
+  /// Ensures that every character of the tag is a valid character.
+  ///
+  /// Every character (in its 7-bit representation) from the Unicode
+  /// character U+0023 to the U+007E is valid for an ETag hash.
+  /// Also the exclamation character which is represented by the Unicode
+  /// code U+0021 and the padding character U+0080.
+  fn is_valid_tag(slice: &str) -> bool {
+    slice.bytes().all(|c| c == b'\x21' || (c >= b'\x23' && c <= b'\x7e') | (c >= b'\x80'))
+  }
+}
+
+impl Into<HttpHeader> for ETag {
+  fn into(self) -> HttpHeader {
+     HttpHeader(String::from("ETag"), self.value)
+  }
+}
diff --git a/src/server/header/http_header.rs b/src/server/header/http_header.rs
new file mode 100644
index 00000000..516f66bf
--- /dev/null
+++ b/src/server/header/http_header.rs
@@ -0,0 +1,19 @@
+use ascii::AsciiString;
+use tiny_http::Header;
+
+pub struct HttpHeader(pub String, pub String);
+
+impl From<Header> for HttpHeader {
+  fn from(header: Header) -> Self {
+    Self(header.field.to_string(), header.value.to_string())
+  }
+}
+
+impl Into<Header> for HttpHeader {
+  fn into(self) -> Header {
+    Header {
+      field: self.0.parse().unwrap(),
+      value: AsciiString::from_ascii(self.1).unwrap(),
+    }
+  }
+}
diff --git a/src/server/header/mod.rs b/src/server/header/mod.rs
new file mode 100644
index 00000000..d4bf72d4
--- /dev/null
+++ b/src/server/header/mod.rs
@@ -0,0 +1,5 @@
+mod etag;
+mod http_header;
+
+pub use etag::*;
+pub use http_header::*;
diff --git a/src/server/mod.rs b/src/server/mod.rs
index 61a62336..8290334d 100644
--- a/src/server/mod.rs
+++ b/src/server/mod.rs
@@ -1,5 +1,5 @@
-mod etag;
+mod header;
 mod http;
 
-pub use etag::*;
+pub use header::*;
 pub use http::*;

From e414cf1b3948511eaf2c04e2a6bbd6f5c4be155c Mon Sep 17 00:00:00 2001
From: Esteban Borai <estebanborai@gmail.com>
Date: Sat, 17 Oct 2020 01:31:41 -0300
Subject: [PATCH 4/4] fmt: format code

---
 src/server/header/etag.rs | 82 +++++++++++++++++++++++++--------------
 1 file changed, 52 insertions(+), 30 deletions(-)

diff --git a/src/server/header/etag.rs b/src/server/header/etag.rs
index 652d9edd..09c326e5 100644
--- a/src/server/header/etag.rs
+++ b/src/server/header/etag.rs
@@ -2,6 +2,18 @@ use crate::server::header::HttpHeader;
 use std::fs::Metadata;
 use std::time::{SystemTime, UNIX_EPOCH};
 
+/// Exclamation point (!) 7-bit character representation
+const EXCLAMATION_CHARACTER: u8 = b'\x21';
+
+/// Hastag (#) 7-bit character representation
+const HASHTAG_SYMBOL: u8 = b'\x23';
+
+/// Closing Curly Brace (}) 7-bit character representation
+const CLOSING_CURLY_BRACE: u8 = b'\x7e';
+
+/// Padding character 7-bit representation
+const PADDING_CHARACTER: u8 = b'\x80';
+
 /// The ETag response-header field provides the current value of the entity tag
 /// for the requested variant. The headers used with entity tags are described in
 /// sections 14.24, 14.26 and 14.44. The entity tag MAY be used for comparison
@@ -36,45 +48,55 @@ use std::time::{SystemTime, UNIX_EPOCH};
 /// * [W3 RFC2616 - Sec 2](https://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2)
 /// * [W3 RFC2616 - Sec 14](https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.19)
 pub struct ETag {
-  value: String,
+    value: String,
 }
 
 impl ETag {
-  /// Creates an **strong** entity tag from the
-  /// provided metadata
-  pub fn from_metadata(meta: &Metadata) -> Result<Self, ()> {
-    let time_created = meta.created().unwrap_or(SystemTime::now())
-      .duration_since(UNIX_EPOCH)
-      .unwrap();
+    /// Creates an **strong** entity tag from the
+    /// provided metadata
+    pub fn from_metadata(meta: &Metadata) -> Result<Self, ()> {
+        let time_created = meta
+            .created()
+            .unwrap_or(SystemTime::now())
+            .duration_since(UNIX_EPOCH)
+            .unwrap();
 
-    let time_modified = meta.modified().unwrap_or(SystemTime::now())
-      .duration_since(UNIX_EPOCH)
-      .unwrap();
+        let time_modified = meta
+            .modified()
+            .unwrap_or(SystemTime::now())
+            .duration_since(UNIX_EPOCH)
+            .unwrap();
 
-    let tag = format!("{:x}{:x}{:x}", time_created.subsec_millis(), time_modified.subsec_millis(), meta.len());
+        let tag = format!(
+            "{:x}{:x}{:x}",
+            time_created.subsec_millis(),
+            time_modified.subsec_millis(),
+            meta.len()
+        );
 
-    if ETag::is_valid_tag(&tag) {
-      return Ok(Self {
-        value: tag
-      })
-    }
+        if ETag::is_valid_tag(&tag) {
+            return Ok(Self { value: tag });
+        }
 
-    Err(())
-  }
+        Err(())
+    }
 
-  /// Ensures that every character of the tag is a valid character.
-  ///
-  /// Every character (in its 7-bit representation) from the Unicode
-  /// character U+0023 to the U+007E is valid for an ETag hash.
-  /// Also the exclamation character which is represented by the Unicode
-  /// code U+0021 and the padding character U+0080.
-  fn is_valid_tag(slice: &str) -> bool {
-    slice.bytes().all(|c| c == b'\x21' || (c >= b'\x23' && c <= b'\x7e') | (c >= b'\x80'))
-  }
+    /// Ensures that every character of the tag is a valid character.
+    ///
+    /// Every character (in its 7-bit representation) from the Unicode
+    /// character U+0023 to the U+007E is valid for an ETag hash.
+    /// Also the exclamation character which is represented by the Unicode
+    /// code U+0021 and the padding character U+0080.
+    fn is_valid_tag(slice: &str) -> bool {
+        slice.bytes().all(|c| {
+            c == EXCLAMATION_CHARACTER
+                || (c >= HASHTAG_SYMBOL && c <= CLOSING_CURLY_BRACE) | (c >= PADDING_CHARACTER)
+        })
+    }
 }
 
 impl Into<HttpHeader> for ETag {
-  fn into(self) -> HttpHeader {
-     HttpHeader(String::from("ETag"), self.value)
-  }
+    fn into(self) -> HttpHeader {
+        HttpHeader(String::from("ETag"), self.value)
+    }
 }