Simple Web API Server in Golang (1)

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

To be an better Gopher, get your hands dirty. Topcoder offered a serials of challenges for learning Golang.

In this blog, I tried to implement "Go Learning Challenge - Simple Web-API Server"[1].

What's used in this challenge ? Following aspects and packages will be covered in this challenge

• How to create a HTTP server: net/http
• How to create routers (handlers for different URLs): regex + url
• How to write HTTP responses: net/http
• How to load JSON config: json + io/ioutil
• How to parse URL query string: url
• How to encode data in sha256/base64: sha256/base64  + strings
• How to write tests in Golang: testing
• How to parse command line arguments: flag
• How to log: log

Configuration File example:

[    {        "domain": "topcoder.com",        "users": [            {                "username": "takumi",                "password": "ilovego"            },            {                "username": "teru",                "password": "ilovejava"            },            {                "username": "toshi",                "password": "iloveapex"            }        ]    },    {        "domain": "appirio.com",        "users": [            {                "username": "jun",                "password": "ilovetopcoder"            },            {                "username": "narinder",                "password": "ilovesamurai"            },            {                "username": "chris",                "password": "ilovesushi"            }        ]    }]

config.go

package SimpleWebAPIServerimport (    "io/ioutil"    "encoding/json"    "errors")type User struct {    UserName string `json:"username"`    Password string `json:"password"`}type Domain struct {    Name string `json:"domain"`    Users UserList `json:"users"`}type DomainWarehouse []Domaintype UserList []Userfunc ReadConfig(fn string) (DomainWarehouse, error) {    data, err := ioutil.ReadFile(fn)    if err != nil {        return nil, err    }    //fmt.Println(string(data))    var m DomainWarehouse    json.Unmarshal(data, &m)    return m, nil}func (dw DomainWarehouse) GetDomain(name string) (*Domain, error) {    for _, domain := range dw {        if domain.Name == name {            return &domain, nil        }    }    return nil, errors.New("Failed to find domain")}func (ul UserList) GetUser(username string) (*User, error) {    for _, user := range ul {        if user.UserName == username {            return &user, nil        }    }    return nil, errors.New("Failed to find user")}

 

tests for config.go

package SimpleWebAPIServerimport (    "testing"    "fmt")func TestReadConfig(t *testing.T) {    dw, err := ReadConfig("./users.json")    if err != nil {        fmt.Println(err)        t.Error("Failed to read config")    }    if dw == nil || len(dw) != 2 {        t.Error("Failed to unmarshal json objects")    }    if dw[0].Name != "topcoder.com" || len(dw[0].Users) != 3 {        t.Error("Incorrect value")    }}func TestGetDomain(t *testing.T) {    dw, err := ReadConfig("./users.json")    if err != nil {        fmt.Println(err)        t.Error("Failed to read config")    }    domain, err := dw.GetDomain("topcoder.com")    if err != nil {        fmt.Println(err)        t.Error("Failed to get domain")    }    if domain.Name != "topcoder.com" || len(domain.Users) != 3 {        t.Error("Incorrect value")    }}func TestGetUser(t *testing.T) {    dw, err := ReadConfig("./users.json")    if err != nil {        fmt.Println(err)        t.Error("Failed to read config")    }    domain, err := dw.GetDomain("topcoder.com")    if err != nil {        fmt.Println(err)        t.Error("Failed to get domain")    }    if domain.Name != "topcoder.com" || len(domain.Users) != 3 {        t.Error("Incorrect value")    }    ul := domain.Users    u, err := ul.GetUser("takumi")    if err != nil {        t.Error("Failed to get user")    }    if u.UserName != "takumi" || u.Password != "ilovego" {        t.Error("Invalid user values")    }}

 

 

After implementing this simple web api server, I got better understanding of Golang syntax and Web API stuffs. For more Web API server challenges, go to [3] about OAuth2.

 

[1] topcoder : http://www.topcoder.com/challenge-details/30046011/?type=develop&noncache=true

[2] git : https://coding.net/u/huys03/p/SimpleWebAPIServer/git

[3] next challenge: http://www.topcoder.com/challenge-details/30046224/?type=develop