Hero
Hero is a handy, fast and powerful go template engine, which pre-compiles the html templtes to go code. It has been used in production environment in bthub.io.
Features
- Easy to use.
- Powerful. template
Extend
andInclude
supported. - High performance.
- Auto compiling when files change.
Install
go get github.com/shiyanhui/hero
go install github.com/shiyanhui/hero/hero
Usage
hero [options]
options:
- source: the html template file or dir.
- dest: generated golang files dir, it will be the same with source if not set.
- pkgname: the generated template package name, default is `template`.
- watch: whether automic compile when the source files change.
example:
hero -source="./"
hero -source="$GOPATH/src/app/template" -watch
Quick Start
Assume that we are going to render a user list userlist.html
. index.html
is the layout, and user.html
is an item in the list.
And assumes that they are all under $GOPATH/src/app/template
index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<%@ body { %>
<% } %>
</body>
</html>
users.html
<%: func UserList(userList []string) []byte %>
<%~ "index.html" %>
<%@ body { %>
<% for _, user := range userList { %>
<ul>
<%+ "user.html" %>
</ul>
<% } %>
<% } %>
user.html
<li>
<%= user %>
</li>
Then we compile the templates to go code.
hero -source="$GOPATH/src/app/template"
We will get three new .go
files under $GOPATH/src/app/template
,
i.e. index.html.go
, user.html.go
and userlist.html.go
.
Then we write a http server in $GOPATH/src/app/main.go
.
main.go
package main
import (
"app/template"
"net/http"
)
func main() {
http.HandleFunc("/users", func(w http.ResponseWriter, req *http.Request) {
var userList = []string {
"Alice",
"Bob",
"Tom",
}
w.Write(template.UserList(userList))
})
http.ListenAndServe(":8080", nil)
}
At last, start the server and visit http://localhost:8080/users
in your browser, we will get what we want!
Template syntax
There are only nine necessary kinds of statements, which are:
-
Function Definition
<%: func define %>
- Function definition statement defines the function which represents a html file.
- The function defined should return one and only one parameter
[]byte
. - Example:
<%: func UserList(userList []string) []byte %>
, which we have mentioned in quick start.
-
Extend
<%~ "parent template" %>
- Extend statement states the parent template the current template extends.
- The parent template should be quoted with
""
. - Example:
<%~ "index.html" >
, which we have mentioned in quick start, too.
-
Include
<%+ "sub template" %>
- Include statement includes a sub-template to the current template. It works like
#include
inC++
. - The sub-template should be quoted with
""
. - Example:
<%+ "user.html" >
, which we also have mentioned in quick start.
- Include statement includes a sub-template to the current template. It works like
-
Import
<%! go code %>
-
Import statement imports the packages used in the defined function, and it also contains everything that is outside of the defined function.
-
Import statement will NOT be inherited by child template.
-
Example:
<%! import ( "fmt" "strings" ) var a int const b = "hello, world" func Add(a, b int) int { return a + b } type S struct { Name string } func (s S) String() string { return s.Name } %>
-
-
Block
<%@ blockName { %> <% } %>
-
Block statement represents a block. Child template overwrites blocks to extend parent template.
-
Example:
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> </head> <body> <%@ body { %> <% } %> </body> </html>
-
-
Code
<% go code %>
-
Code statement states all code inside the defined function. It's just go code.
-
Example:
<% for _, user := userList { %> <% if user != "Alice" { %> <%= user %> <% } %> <% } %> <% a, b := 1, 2 c := Add(a, b) %>
-
-
Raw Value
<%== statement %>
-
Raw Value statement will convert the variable to string.
-
Example:
<%== a %> <%== a + b %> <%== Add(a, b) %> <%== user.Name %>
-
-
Escaped Value
<%= statement %>
-
Escaped Value statement is similar with Raw Value statement, but after converting, it will escaped it with
html.EscapesString
. -
Example:
<%= a %> <%= a + b %> <%= Add(a, b) %> <%= user.Name %>
-
-
Note
<%# note %>
- Note statement add notes to the template.
- It will not be added to the generated go source.
- Example:
<# this is just a note example>
.
License
Hero is licensed under the Apache License.