Merge branch 'master' of github.com:marciok/katan

* 'master' of github.com:marciok/katan:
  Add images
  Add breakline
  Add references
  Remove header
  Update README.md
  Update README

Author: marciok

README.md

@@ -1,22 +1,22 @@
  # Katan
  A micro web server that replies *"Hello world!"* to every request
 
- The ideia is to show the basics steps to create a web server in Swift.
+ The idea is to show the basics steps to create a web server in Swift.
 
  *An web server overview:*
 
- ![alt text](cloud+flow_final.png)
+ ![alt text](https://s3.amazonaws.com/marcioklepacz/cloud%2Bflow_final.png)
 
 
  ## 1. Create Socket 🐣
 
-```swift
-    let socketDescriptor = Darwin.socket(AF_INET, SOCK_STREAM, 0)
-```
+ ```swift
+func startWebServer(){
 
- *int socket(int domain, int type, int protocol);*
- 
- Creates an endpoint for communication and returns a descriptor.
+    let socketDescriptor = Darwin.socket(AF_INET, SOCK_STREAM, 0)
+```    
+
+ `socket` -- creates an endpoint for communication and returns a descriptor.
 
  **domain**: Communication domain, selects the protocol family, in our case ipv4 (AF_INET). AF_INET6 if we wanted to use ipv6.
 
@@ -27,28 +27,28 @@
 
  Returns -1 if there's an error otherwise the descriptor (a reference).
 
+
  ## 2. Set options 🎛
-```swift    
+
+ ```swift  
     var noSigPipe: Int32 = 1
     setsockopt(socketDescriptor, SOL_SOCKET, SO_NOSIGPIPE, &noSigPipe, socklen_t(MemoryLayout<Int32>.size))
 ```
-
- `int setsockopt(int socket, int level, int option_name, const void *option_value, socklen_t option_len);`
+ `setsockopt` -- get and set options on sockets
 
  **socket**: The socket descriptor
 
- **level**: To manipulate options at
- 
- the socket level, level is specified as SOL_SOCKET
- option_name: The name of our the option, in our case we do not generate SIGPIPE, instead return EPIPE
+ **level**: To manipulate options at the socket level
+     
+ **option_name**: The name of our the option, in our case we do not generate SIGPIPE, instead return EPIPE
  A SIGPIPE is sent to a process if it tried to write to a socket that had been shutdown for writing or isn't connected (anymore).
 
  **socklen_t**: the option length
 
  ## 3. Create adress and bind 🚪➕🔌
 
- ![alt text](overview.png)
-```swfit
+ ![alt text](https://s3.amazonaws.com/marcioklepacz/overview.png)
+ ```swift
     let port: in_port_t = 9292
 
     var address = sockaddr_in(
@@ -58,45 +58,41 @@
         sin_addr: in_addr(s_addr: in_addr_t(0)),
         sin_zero:(0, 0, 0, 0, 0, 0, 0, 0) // Add some padding, more info at: http://stackoverflow.com/questions/15608707/why-is-zero-padding-needed-in-sockaddr-in#15609050
     )
-    
+
     var bindResult: Int32 = -1
     bindResult = withUnsafePointer(to: &address) {
         bind(socketDescriptor, UnsafePointer<sockaddr>(OpaquePointer($0)), socklen_t(MemoryLayout<sockaddr_in>.size))
     }
-```
-
-bind a name to a socket
+  ```  
 
- `int bind(int socket, const struct sockaddr *address, socklen_t address_len);`
+`bind` -- assigns a name to an unnamed socket.
 
- bind() assigns a name to an unnamed socket.  When a socket is created
- with socket() it exists in a name space (address family) but has no name
- assigned.  bind() requests that address be assigned to the socket.
+  When a socket is created with socket() it exists in a name space (address family) but has no name
+ assigned. bind() requests that address be assigned to the socket.
 
- */
-    
+ ```swift 
     if bindResult == -1 {
         fatalError(String(cString: UnsafePointer(strerror(errno))))
     }
 
-/*:
+```
+
  ## 4. Listen 📡
- */
+```swift
     listen(socketDescriptor, SOMAXCONN)
-/*:
- listen for connections on a socket 
- `int listen(int socket, int backlog);`
+```
+ `listen` -- for connections on a socket
 
  The backlog parameter defines the maximum length for the queue of pending
  connections.  If a connection request arrives with the queue full, the
  client may receive an error with an indication of ECONNREFUSED.
 
- */
+ 
+
 
-/*:
  ## 5.  Accept connection on socket ✅
-*/
-    
+
+  ```swift  
     print("Starting HTTP server on port \(port)")
     repeat {
         var address = sockaddr()
@@ -106,11 +102,10 @@ bind a name to a socket
         if clientSocket == -1 {
             fatalError(String(cString: UnsafePointer(strerror(errno))))
         }
-/*:
- `int accept(int socket, struct sockaddr *restrict address, socklen_t *restrict address_len);`
- 
- accept() extracts the first connection request on the queue
- of pending connections, creates a new socket with the same properties of
+```
+`accept` -- extracts the first connection request on the queue of pending connections,
+         
+ Creates a new socket with the same properties of
  socket, and allocates a new file descriptor for the socket.
 
  The argument address is a result parameter that is filled in with the
@@ -120,62 +115,59 @@ bind a name to a socket
  parameter; it should initially contain the amount of space pointed to by
  address; on return it will contain the actual length (in bytes) of the
  address returned.
- */
+ ```swift
 
         var characters = ""
-        var next: UInt8 = 0
+        var received: UInt8 = 0
         repeat {
             var buffer = [UInt8](repeatElement(0, count: 1))
 
 
-/*:
+```
 ## 6. Read socket 📖
 
-recv -- receive a message from a socket
+`recv` -- receive a message from a socket
 
-`ssize_t recv(int socket, void *buffer, size_t length, int flags);`
-*/
+```swift
             let resp = recv(clientSocket, &buffer, Int(buffer.count), 0)
             if resp <= 0 {
                 fatalError(String(cString: UnsafePointer(strerror(errno))))
             }
 
-            next = buffer[0]
-            if next > 13 /* Carriage Return */ {
-                characters.append(Character(UnicodeScalar(next)))
+            received = buffer.first!
+            if received > 13 /* Carriage Return on ASCII table */ {
+                characters.append(Character(UnicodeScalar(received)))
             }
-        } while next != 10 /* New Line */
+        } while received != 10 /* New Line on ASCII table */
 
         print("Received -> \(characters)")
+```
+## 7. Write response 📝
+
+`write` -- write output
+```swift
         let message = "HTTP/1.1 200 OK\r\n\r\n Hello World!"
         print("Response -> \(message)")
         let messageData = ArraySlice(message.utf8)
 
         _ = messageData.withUnsafeBytes {
-/*:
-## 7. Write response 📝
-
-write -- write output
-
-`ssize_t write(int fildes, const void *buf, size_t nbyte);`
-*/
 
             write(clientSocket, $0.baseAddress, messageData.count)
         }
 
-/*:
+```
 ## 8. Close socket ⚰️
 
-close -- delete a descriptor
+`close` -- delete a descriptor
+```swift
 
-`int close(int fildes);`
-*/
         close(clientSocket)
 
     } while true
 
-
-
-
-
-
+}
+startWebServer()
+```
+# References:
+* https://ruslanspivak.com/lsbaws-part1/
+* https://github.com/httpswift/swifter