Add HTML template renderer (#29)

* Add HTML template renderer * Fix comment * Template example, missed imports * Update readme
DronRathore · Feb 17, 2019 · 62f79f0 · 62f79f0
1 parent 3a7ad4a
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diff --git a/README.md b/README.md
@@ -211,6 +211,28 @@ func(req *express.Request, res *express.Response){
 }
 ```
 
+## HTML Template
+
+Use [standard Golang http templates](https://golang.org/pkg/html/template/) to render response page.
+
+For example, you have a template file `index.html` in `templates` directory:
+
+```html
+<h1>{{.Name}}</h1>
+```
+
+Fill the context and provide a path to the template file:
+
+```go
+func(req *express.Request, res *express.Response){
+  type TmplContext struct{
+    Name string
+  }
+  data := TmplContext{"Rob"}
+  res.Render("template.html", &data)
+}
+```
+
 ## Safe Cleanup on exit
 
 Newer version of goexpress provides three new methods namely `express.ShutdownTimeout`, `express.BeforeShutdown` and `express.Shutdown`, these methods can be utilised to do cleanup before the server shuts down.

diff --git a/examples/render/render.go b/examples/render/render.go
@@ -0,0 +1,23 @@
+package main
+
+import (
+  "github.com/DronRathore/goexpress"
+)
+
+type Context struct {
+  Greeting string
+  Subject  string
+}
+
+func main() {
+  express := goexpress.Express()
+  // return rendered template
+  express.Get("/", func(req goexpress.Request, res goexpress.Response) {
+    data := Context{
+      Greeting: "Hello",
+      Subject: "world",
+    }
+    res.Render("template.html", data)
+  })
+  express.Start("8080")
+}
diff --git a/examples/render/template.html b/examples/render/template.html
@@ -0,0 +1,5 @@
+<html>
+<body>
+<h1>{{.Greeting}}, {{.Subject}}!</h1>
+</body>
+</html>
diff --git a/interface.go b/interface.go
@@ -53,6 +53,7 @@ type Response interface {
   SendFile(url string, noCache bool) bool
   WriteBytes(bytes []byte) error
   Write(content string) Response
+  Render(path string, data interface{})
 }
 
 // Header defines HTTP header interface

diff --git a/response.go b/response.go
@@ -3,11 +3,13 @@
 package goexpress
 
 import (
+  "bytes"
   "bufio"
   "crypto/md5"
   "encoding/hex"
   "encoding/json"
   "fmt"
+  "html/template"
   "io"
   "log"
   "net"
@@ -307,3 +309,27 @@ func (res *response) Header() Header {
 func (res *response) Cookie() Cookie {
   return res.cookie
 }
+
+// Render returns rendered HTML template
+func (res *response) Render(file string, data interface{}) {
+  tmpl, err := template.ParseFiles(file)
+  if err != nil {
+    log.Print("Template not found ", err)
+    res.header.SetStatus(500)
+    res.header.FlushHeaders()
+    res.End()
+    return
+  }
+
+  var tpl bytes.Buffer
+  err = tmpl.Execute(&tpl, data)
+  if err != nil {
+    log.Print("Template render failed ", err)
+    res.header.SetStatus(500)
+    res.header.FlushHeaders()
+    res.End()
+    return
+  }
+  res.WriteBytes(tpl.Bytes())
+}
+