guinso/MixedWebHosting.go

## MixedWebHosting.go
/**
This web server serve 2 different type request: [static file] and [dynamic path]
[Static file] URL path: /*
[Dynamic Path] URL path: /api/*

Preparation:
1) Create "static-files" directory to place all static file like index.html
2) Create "dynamic-files" diectory to place all dynamic or hidden logical files, example invoice.pdf
3) Place "index.html" at root of "static-files" directory
4) Place "neon.jpg" (any kind of JPEG file) at root of "dynamic-files" directory

Sample URL:
1) http://localhost:7777/               - show static html file
2) http://localhost:7777/api/meals      - demo GET Json request
3) http://localhost:7777/api/img/12345  - demo dynamic image request
**/

package main

import (
  "fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strings"
)

func main() {
	// handler all request start from "/"
	http.HandleFunc("/", handler)

	// start HTTP server in socket 7777
	http.ListenAndServe(":7777", nil)

	// start HTTPS server (default socket 443)
	//x http.ListenAndServeTLS("/", "abc.crt", "abc.key", handler)
}

// Handle HTTP request to either static file server or REST server (URL start with "api/")
func handler(w http.ResponseWriter, r *http.Request) {
  	//remove first "/" character
	urlPath := r.URL.Path[1:]

  	//if start with "api/" direct to REST handler
	if strings.HasPrefix(urlPath, "api/") {
		//trim prefix "api/"
		trimmedURL := urlPath[4:]
		/*
			//trim suffix "/"
			if strings.HasSuffix(trimmedURL, "/") {
				trimmedURL = trimmedURL[0:(len(trimmedURL) - 1)]
			}
		*/

		routePath(w, r, trimmedURL)
	} else {
		log.Print("Entering static file handler: " + urlPath)

		// define your static file directory
		staticFilePath := "./static-files/"

		//other wise, let read a file path and display to client
		http.ServeFile(w, r, staticFilePath + urlPath)
	}
}

//handle dynamic HTTP user requset
func routePath(w http.ResponseWriter, r *http.Request, trimURL string) {
	// find and match trimmed URL to respective REST request
	//      trimmed URL
	//      request method
	//      input parameter(s)

	if strings.HasPrefix(trimURL, "login") {
    		// example URL: localhost:7777/api/login
		// TODO: handle login request
		fmt.Fprint(w, "Request login")
	} else if strings.HasPrefix(trimURL, "logout") {
    		// example URL: localhost:7777/api/logout
		// TODO: handle logout request
		fmt.Fprint(w, "Request logout")
	} else if strings.HasPrefix(trimURL, "meals") {
    		// example URL: localhost:7777/api/meals
		// show list of meals
		w.Header().Set("Content-Type", "application/json") //MIME to application/json
		w.WriteHeader(http.StatusOK)                       //status code 200, OK
		w.Write([]byte("{ msg: \"this is meal A \" }"))    //body text
	} else if strings.HasPrefix(trimURL, "img/") {
    		// example URL: localhost:7777/api/img/
		// show image file to client dynamically

    		logicalFilePath := "./logic-files/"
    		physicalFileName := "neon.jpg"

    		// try read file
		data, err := ioutil.ReadFile(logicalFilePath + physicalFileName)
		if err != nil {
      			// show error page if failed to read file
			handleErrorCode(500, "Unable to retrieve image file", w)
		} else {
			//w.Header().Set("Content-Type", "image/jpg") // #optional HTTP header info

			// uncomment if image file is meant to download instead of display on web browser
			// clientDisplayFileName = "customName.jpg"
			//w.header().Set("Content-Disposition", "attachment; filename=\"" + clientDisplayFileName + "\"")

			// write file (in binary format) direct into HTTP return content
      			w.Write(data)
		}

	} else {
		// show error code 404 not found
		handleErrorCode(404, "Path not found.", w)
	}
}

// Generate error page
func handleErrorCode(errorCode int, description string, w http.ResponseWriter) {
	w.WriteHeader(errorCode) // set HTTP status code (example 404, 500)
	w.Header().Set("Content-Type", "text/html") // clarify return type (MIME)
	w.Write([]byte(fmt.Sprintf(
		"<html><body><h1>Error %d</h1><p>%s</p></body></html>",
		errorCode,
		description)))
}
	/**
	This web server serve 2 different type request: [static file] and [dynamic path]
	[Static file] URL path: /*
	[Dynamic Path] URL path: /api/*

	Preparation:
	1) Create "static-files" directory to place all static file like index.html
	2) Create "dynamic-files" diectory to place all dynamic or hidden logical files, example invoice.pdf
	3) Place "index.html" at root of "static-files" directory
	4) Place "neon.jpg" (any kind of JPEG file) at root of "dynamic-files" directory

	Sample URL:
	1) http://localhost:7777/ - show static html file
	2) http://localhost:7777/api/meals - demo GET Json request
	3) http://localhost:7777/api/img/12345 - demo dynamic image request
	**/

	package main

	import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strings"
	)

	func main() {
	// handler all request start from "/"
	http.HandleFunc("/", handler)

	// start HTTP server in socket 7777
	http.ListenAndServe(":7777", nil)

	// start HTTPS server (default socket 443)
	//x http.ListenAndServeTLS("/", "abc.crt", "abc.key", handler)
	}

	// Handle HTTP request to either static file server or REST server (URL start with "api/")
	func handler(w http.ResponseWriter, r *http.Request) {
	//remove first "/" character
	urlPath := r.URL.Path[1:]

	//if start with "api/" direct to REST handler
	if strings.HasPrefix(urlPath, "api/") {
	//trim prefix "api/"
	trimmedURL := urlPath[4:]
	/*
	//trim suffix "/"
	if strings.HasSuffix(trimmedURL, "/") {
	trimmedURL = trimmedURL[0:(len(trimmedURL) - 1)]
	}
	*/

	routePath(w, r, trimmedURL)
	} else {
	log.Print("Entering static file handler: " + urlPath)

	// define your static file directory
	staticFilePath := "./static-files/"

	//other wise, let read a file path and display to client
	http.ServeFile(w, r, staticFilePath + urlPath)
	}
	}

	//handle dynamic HTTP user requset
	func routePath(w http.ResponseWriter, r *http.Request, trimURL string) {
	// find and match trimmed URL to respective REST request
	// trimmed URL
	// request method
	// input parameter(s)

	if strings.HasPrefix(trimURL, "login") {
	// example URL: localhost:7777/api/login
	// TODO: handle login request
	fmt.Fprint(w, "Request login")
	} else if strings.HasPrefix(trimURL, "logout") {
	// example URL: localhost:7777/api/logout
	// TODO: handle logout request
	fmt.Fprint(w, "Request logout")
	} else if strings.HasPrefix(trimURL, "meals") {
	// example URL: localhost:7777/api/meals
	// show list of meals
	w.Header().Set("Content-Type", "application/json") //MIME to application/json
	w.WriteHeader(http.StatusOK) //status code 200, OK
	w.Write([]byte("{ msg: \"this is meal A \" }")) //body text
	} else if strings.HasPrefix(trimURL, "img/") {
	// example URL: localhost:7777/api/img/
	// show image file to client dynamically

	logicalFilePath := "./logic-files/"
	physicalFileName := "neon.jpg"

	// try read file
	data, err := ioutil.ReadFile(logicalFilePath + physicalFileName)
	if err != nil {
	// show error page if failed to read file
	handleErrorCode(500, "Unable to retrieve image file", w)
	} else {
	//w.Header().Set("Content-Type", "image/jpg") // #optional HTTP header info

	// uncomment if image file is meant to download instead of display on web browser
	// clientDisplayFileName = "customName.jpg"
	//w.header().Set("Content-Disposition", "attachment; filename=\"" + clientDisplayFileName + "\"")

	// write file (in binary format) direct into HTTP return content
	w.Write(data)
	}

	} else {
	// show error code 404 not found
	handleErrorCode(404, "Path not found.", w)
	}
	}

	// Generate error page
	func handleErrorCode(errorCode int, description string, w http.ResponseWriter) {
	w.WriteHeader(errorCode) // set HTTP status code (example 404, 500)
	w.Header().Set("Content-Type", "text/html") // clarify return type (MIME)
	w.Write([]byte(fmt.Sprintf(
	"<html><body><h1>Error %d</h1><p>%s</p></body></html>",
	errorCode,
	description)))
	}