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About Me
Building Go applications
About Me
Lawyer (1-2 yrs)
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS
(codeacademy, books, websites)
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS mid-Jul 2014: Go (1st backend)
(codeacademy, books, websites)
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS mid-Jul 2014: Go (1st backend)
(codeacademy, books, websites)
(everywhere)
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS mid-Jul 2014: Go (1st backend) mid-Aug 2014: deployed 1st app – CRUD app
(codeacademy, books, websites)
(everywhere)
About Me
Lawyer (1-2 yrs)
Learning Journey May – Jul 2014: HTML, CSS, JS mid-Jul 2014: Go (1st backend)mid-Aug 2014: deployed 1st app – CRUD app end-Aug 2014: deployed 2nd app – API client
(codeacademy, books, websites)
(everywhere)
Go Resources
golang.org
Books and websites
Sample applications
Stackoverflow, Go-nuts mailing list
Go Resources
golang.org (Go Tour, Docs, Go blog)
Books and websites
Sample applications
Stackoverflow, Go-nuts mailing list
Go Resources
golang.org (Go Tour, Docs, Go blog)
Books and websites (www.golang-book.com, www.gobyexample.com)
Sample applications
Stackoverflow, Go-nuts mailing list
Go Resources
golang.org (Go Tour, Docs, Go blog)
Books and websites (www.golang-book.com, www.gobyexample.com)
Sample applications (Go Wiki, from books)
Stackoverflow, Go-nuts mailing list
Experience with Go
Building Go applications
CRUD App
API Client
Flickr, Weather API
Simple CRUD App using MySQL for data persistence
1st app: CRUD App
Sign up/Sign in
Read Status
Create Status
Delete Status
Edit Status
Sign out
MySQL
Basic Structure
package main
Import (“fmt”“net/http”
)
func handler(w http.ResponseWriter, r *http.Request) {fmt.Fprint(w, “hello world!”)
}
func main() {http.HandleFunc(“/”, handler)http.ListenAndServe(“:8080”, nil)
}
Basic Structure
package main
Import (“fmt”“net/http”
)
func handler(w http.ResponseWriter, r *http.Request) {fmt.Fprint(w, “hello world!”)
}
func main() {http.HandleFunc(“/”, handler)http.ListenAndServe(“:8080”, nil)
}Local server connection
Handler function when root is requested
Print output to client
All executable commands use package main
Go’s stdlib
Entry point
Libraries
import ("database/sql""html/template""fmt""log""net/http""os"_ "github.com/go-sql-driver/mysql""github.com/gorilla/mux""github.com/gorilla/securecookie”
)
Libraries
Standard library
import ("database/sql""html/template""fmt""log""net/http""os"_ "github.com/go-sql-driver/mysql""github.com/gorilla/mux""github.com/gorilla/securecookie”
)
External packages
Data Structs
Type Slice of Pointers to Post struct
type User struct {Userid int64Username stringPassword stringPosts []*Post
}
type Post struct {Tweetid stringUsername stringStatus string
}
Database functions
Return slice of slice of stringsfunc ReadStatus() (res [][]string) {err := db.Ping()if err != nil {
log.Fatal(err)}rows, err := db.Query("SELECT id, tweet, username FROM posts WHERE username = ? ORDER BY id DESC", currentuser)if err != nil {
log.Fatal(err)}defer rows.Close()
var tweet, id, username stringfor rows.Next() {
err := rows.Scan(&id, &tweet, &username)if err != nil {
return res}var a []stringa = append(a, id, tweet, username)res = append(res, a)
}return
}
Database functions
Return slice of slice of stringsfunc ReadStatus() (res [][]string) {err := db.Ping()if err != nil {
log.Fatal(err)}rows, err := db.Query("SELECT id, tweet, username FROM posts WHERE username = ? ORDER BY id DESC", currentuser)if err != nil {
log.Fatal(err)}defer rows.Close()
var tweet, id, username stringfor rows.Next() {
err := rows.Scan(&id, &tweet, &username)if err != nil {
return res}var a []stringa = append(a, id, tweet, username)res = append(res, a)
}return
}
Verify db connection
Raw queries
Append strings to sliceAppend slice of strings to output
Handler functions
Append slice of Post instances to Posts slice
func homeHandler(w http.ResponseWriter, r *http.Request) {currentuser = getUserName(r)if currentuser != "" {
var as []Posta := User{}m := ReadStatus()
for i := 0; i < len(m); i++ {as = append(as, Post{Tweetid: m[i][0], Username: currentuser, Status: m[i][1]})
}a = User{Username: currentuser}for i := 0; i < len(m); i++ {
a.Posts = append(a.Posts, &as[i])}
renderTemplate(w, "home", "homepage", a)} else {
http.Redirect(w, r, "/", 302)}
}
Wrapper func around html/template library
Create slice with Post instances
Func main
Open connection pool
Handlers for URL paths
func main() {db, err = sql.Open("mysql",
os.Getenv("DB_USERNAME")+":"+os.Getenv("DB_PASSWORD")+"@tcp("+os.Getenv("DB_CLEARDB")+":3306)/"+os.Getenv("DB_NAME"))
if err != nil {log.Fatal(err)
}defer db.Close()
router.HandleFunc("/", logHandler)router.HandleFunc("/login", loginHandler)router.HandleFunc("/home", homeHandler)router.HandleFunc("/home/tweets", usertweetHandler).Methods("POST")router.HandleFunc("/logout", logoutHandler).Methods("POST")router.HandleFunc("/home/delete", deleteHandler).Methods("POST")router.HandleFunc("/home/edit", editHandler).Methods("POST")router.HandleFunc("/home/save", saveHandler).Methods("POST”)router.PathPrefix("/").Handler(http.FileServer(http.Dir("./layout/")))http.Handle("/", router)
err := http.ListenAndServe(":"+os.Getenv("PORT"), nil)if err != nil {
panic(err)}
}
Port for server connection
2nd app: API Client
Get a series of photos from Flickrfor a random city and displaycurrent weather data for the samecity
Libraries
import ("encoding/json""fmt""html/template""io/ioutil""log""math/rand""net/http""os""strconv""time"
)
https://github.com/AudreyLim/weathergo
https://github.com/AudreyLim/twittergo
Twitter: @AudreyLim77
Thank you.
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