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This article will explain in detail how to use the basic template in Go. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

1. Html/template creates the basic static template package mainimport ("html/template"log"os") func main () {tmpl,err: = template.New ("go-web") .Parse (`Hello World! `) / / first create a template object if err! = nil {log.Fatalf ("Parse:%v", err) / / fatalf format string Print error} err = tmpl.Execute (os.Stdout,nil) / / call method Execute with two parameters: destination Data equals nil if err! = nil {log.Fatal ("Execute:% v", err)}} go run test.go output: Hello words2, output dynamic template package mainimport ("html/template"log"os") func main () {tmpl,err: = template.New ("go-web") .Parse (`Hello worldlings, {{.} `) / / create the output dynamic template package mainimport ("html/template"log"os") first. Dynamic templates that produce different effects {{}}, "." Represents the object "go web" if err! = nil {log.Fatalf ("Parse:%v", err) / / fatalf format string, print error} err = tmpl.Execute (os.Stdout, "go web") / / call method Execute, two parameters: destination Data equals go web first, and the value of the object at this time is go web if err! = nil {log.Fatal ("Execute:% v", err)}} go run test.go output: Hello Worldcup log go webpackage mainimport ("html/template"log"os") type Package struct {/ / Custom incoming type Package Name string NumFuncs int NumVars int} func main () {tmpl Err: = template.New ("go-web") .Parse (`Hello worldstones, {{.}} `) / / first create the data that can be input according to the difference Dynamic templates {{}}, which produce different effects. Represents the object if err! = nil {log.Fatalf ("Parse:%v", err) / / fatalf format string, print error} err = tmpl.Execute (os.Stdout,&Package {/ / custom incoming type Package Name: "go-web", NumFuncs:12, NumVars:1200,}) / / call method Execute, two parameters: destination Data equals go web first, and the value of the object at this time is go web if err! = nil {log.Fatal ("Execute:% v", err)}} go run test.go output: Hello wordings, {go-web 12 1200} how to output the result of template rendering to stdout? Package mainimport ("html/template"log"os") type Package struct {Name string NumFuncs int NumVars int} func main () {tmpl,err: = template.New ("go-web") .Parse (`Parse: {{.Name}} / / find a method, field or function by reflection. Name must be public and must have its initials capitalized. Number of functions: {{.NumFuncs}} Number of variables: {{.NumVars}} `) / / first create a dynamic template that can produce different effects according to the input data. Represents a format string with object if err! = nil {log.Fatalf ("Parse:%v", err) / / fatalf, print error} err = tmpl.Execute (os.Stdout,&Package {Name: "go-web", NumFuncs:12, NumVars:1200,}) / / call method Execute, two parameters: destination Data equals go web first, and the value with the object is go web if err! = nil {log.Fatal ("Execute:% v", err)}} go run test.go output: Package name: go-web Number of functions: 12 Number of variables: 12003, and the template result is output to the http response stream. Visit package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl) through the browser Err: = template.New ("go-web") .Parse (`Parse: {{.Name}} Number of functions: {{.NumFuncs}} Number of variables: {{.NumVars}} `) / / create first according to the input data Dynamic templates {{}}, which produce different effects. Representative and object if err! = nil {fmt.Fprintf (writer, "Parse:%v", err) return} err = tmpl.Execute (writer,&Package {Name: "go-web", NumFuncs:12, NumVars:1200,}) / / call method Execute, two parameters: destination Data equals go web first, and the value of the object is go web if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 10:38:40 Starting Server.... on 2018-07-10

Browser access: http://localhost:4000/

4. Package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl,err: = template.ParseFiles ("main.tmpl") if err! = nil {fmt.Fprintf (writer) "ParseFiles:%v", err) return} err = tmpl.Execute (writer,&Package {Name: "go-web", NumFuncs:14, NumVars:1200,}) / / call method Execute Two parameters: destination, data equals go web, and the value of the object is go web if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} then edit the local main.tmpl file: ➜test pwd/Users/daixuan/qbox/test➜ test vim main.tmplPackage name: {{.Name}} Number of functions: {{.NumFuncs}} Number of variables: {{.NumVars}} go run test.go output: 2018-07-10 10:52:56 Starting Server....

Browser access: http://localhost:4000/

5. How to use http.request template to print out the content we need in the structure ➜test vim main.tmplMethod: {{.Method}} package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl Err: = template.ParseFiles ("main.tmpl") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} err = tmpl.Execute (writer,request) / / calling method Execute Two parameters: destination, data equals go web, and the value of the object is go web if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:01:28 Starting Server.... on 2018-07-10

Browser access: http://localhost:4000/ prints out Method:GET

Modify main.tmplMethod: {{.Method}} URL: {{.URL.Path}}

Browser access: http://localhost:4000/ prints out Path: /

Print User-Agent

Modify main.tmplMethod: {{.Method}} Path: {{.URL.Path}} Header: {{. Header.Get "User-Agent"}} package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl) Err: = template.ParseFiles ("main.tmpl") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} err = tmpl.Execute (writer,request) / / calling method Execute Two parameters: destination, data equals go web, and the value of the object is go web if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:10:01 Starting Server.... on 2018-07-10

Browser access: http://localhost:4000/

6. Create a real html page vim main.html Go Web

Package info:

Package name: {{.Name}} Number of functions: {{.NumFuncs}} Number of variables: {{.NumVars} package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl Err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} err = tmpl.Execute (writer,&Package {Name: "go-web", NumFuncs:14, NumVars:1200 }) if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:24:51 Starting Server.... on 2018-07-10

Browser access: http://localhost:4000/

Right-click to view the source code of the page: view-source: http://localhost:4000/

Go Web

Package info:

Package name: go-web} Number of functions:14} Number of variables: 1200} 7, simple application, according to the score to judge the grade is A _ score B _ score C. First, complete the size of vim main.html Go Web {{.}} package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl) from the request parameters. Err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} score: = request.FormValue ("score") err = tmpl.Execute (writer,score) if err! = nil {fmt.Fprintf (writer, "Execute:%v") Err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:33:01 Starting Server.... on 2018-07-10

Visit: http://localhost:4000/?score=100

Output 100

Visit: http://localhost:4000/?score=1

Output 1

In line with expectations

Determine whether score exists or not

Vim main.html Go Web {{if.}} score is {{else}} no score {{end}} vim test.gopackage mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter) Request * http.Request) {tmpl,err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} score: = request.FormValue ("score") err = tmpl.Execute (writer,score) if err! = nil {fmt.Fprintf (writer, "Execute:%v") Err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:38:10 Starting Server.... on 2018-07-10

Visit: http://localhost:4000/?score=100

Visit: http://localhost:4000/

Compare the numerical values

Vim main.html Go Web {{if gt. 90}} A {{else if gt. 80}} B {{else if gt. 70}} C {{else if gt. 60} D {{else}} F {{end}} error: Execute:template: main.html:6:13: executing "main.html" at: error calling gt: incompatible types for comparison because request.FormValue ("score") returns string type Cannot compare with int 90 to modify the return type vim test.gopackage mainimport ("html/template"log"net/http"fmt"strconv") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl,err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer) "ParseFiles:%v", err) return} score: = request.FormValue ("score") num, _: = strconv.Atoi (score) err = tmpl.Execute (writer,num) if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 11:53:59 Starting Server.... on 2018-07-10

Access: http://localhost:4000/?score=100 output A

Http://localhost:4000/?score=80 output C

Http://localhost:4000/?score=60 output F

8. Range changes the scope vim main.html Go Web {{range $key,$value: = .header}}

Method: {{$.Method}} key: {{$key}}

{{range $value}} {{.}} {{end}}

{{end}} vim test.gopackage mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl,err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v") Err) return} err = tmpl.Execute (writer,request) if err! = nil {fmt.Fprintf (writer, "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 12:14:13 Starting Server.... on 2018-07-10

Http://localhost:4000/

9 、 With changes the scope Go Web {{with .URL}} {{. Scheme}} {{.User}} {{.Host}} {{end}} package mainimport ("html/template"log"net/http"fmt" ) type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/" Func (writer http.ResponseWriter, request * http.Request) {tmpl,err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} err = tmpl.Execute (writer,request) if err! = nil {fmt.Fprintf (writer, "Execute:%v" Err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output:

Access: http://localhost:4000/1234?score=80 output:

/ 1234?score=80 / 1234

10. With changes scope

What if you want to temporarily output some strings and fields in web?

It is inconvenient to maintain a large structure

Change the following object into a map with the key type string and the value type empty interface, and then put all the objects that need to be passed in in the map. In addition, there is another advantage that the map can be declared as a variable and passed in different Handler. Before the Handler of the final response, new content is constantly added to the map. Finally, when the template is rendered, all the content can be used.

Go Web {{.request}} {{.Score}} package mainimport ("html/template"log"net/http"fmt") type Package struct {Name string NumFuncs int NumVars int} func main () {http.HandleFunc ("/", func (writer http.ResponseWriter, request * http.Request) {tmpl Err: = template.ParseFiles ("main.html") if err! = nil {fmt.Fprintf (writer, "ParseFiles:%v", err) return} err = tmpl.Execute (writer, map [string] interface {} {"Request": request, "Score": 97,}) if err! = nil {fmt.Fprintf (writer) "Execute:%v", err) return}}) log.Println ("Starting Server....") Log.Fatal (http.ListenAndServe (": 4000", nil))} go run test.go output: 12:29:10 Starting Server.... on 2018-07-10

Http://localhost:4000/ output score=97 and GET methods

This is the end of the article on "how to use the basic template in Go". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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