Golang's Template package advanced guide: from entry to mastery-Golang-php.cn

Golang's Template package advanced guide: from entry to mastery

王林

Release： 2023-07-17 12:06:14

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Advanced Guide to Golang’s Template Package: From Beginner to Mastery

Introduction
Golang’s Template package is a template engine built into the Go language, providing a convenient and flexible way to generate and render. Text output. In this article, we will start with the basics and go deeper, explaining how to use the Template package and how to optimize and extend your templates through some advanced techniques.

Basic knowledge: Template syntax
Before using the Template package, we need to understand its basic syntax. The template consists of regular text and dynamic operations. Regular text is copied and output directly, while dynamic operations replace it based on the given data. Dynamic operations are surrounded by double curly braces {{}} and processed according to their type. Here are some common template syntax examples:

Output variable value:
```
{{.}}
```
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This will output the value of the current variable.
Conditional judgment:
```
{{if .}}
  条件为真的情况
{{else}}
  条件为假的情况
{{end}}
```
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Different content will be output according to the conditions.
Iteration loop:
```
{{range .}}
  循环体
{{end}}
```
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This will iterate over the given list.

Advanced Tips: Template Inheritance
In addition to basic template syntax, the Template package also supports template inheritance, which is a powerful way to reuse and extend templates. By defining a base template and defining other templates based on it, we can effectively organize and manage template code. The following is an example of using template inheritance:

First, we create a base template base.html:

<!DOCTYPE html>
<html>
<head>
    <title>{{block "title" .}}My Website{{end}}</title>
</head>
<body>
    <div id="content">
        {{block "content" .}}Content{{end}}
    </div>
</body>
</html>

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Then, in other templates, we can extend this base template and re- Define the blocks in it to implement custom content:

{{extend "base.html"}}

{{block "title" .}}
    My Page Title
{{end}}

{{block "content" .}}
    <h1>Welcome to my website!</h1>
{{end}}

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In this way, we can define multiple templates concisely without repeatedly writing common HTML code.

Advanced Tips: Custom Functions
The Template package allows us to customize functions and call them in templates, which is a very useful feature. Through custom functions, we can perform various custom operations, such as formatting dates, calculating mathematical formulas, etc. Here is an example of a custom function:

First, we define a custom function:

func toUpper(str string) string {
    return strings.ToUpper(str)
}

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Then, in the template, we can call the function:

{{.Name | toUpper}}

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In this example, we have a Name field in the data and we pass it to the custom function toUpper which converts the value of the Name field to uppercase.

Optimization Tips: Precompile Templates
When processing a large number of templates, precompiled templates can improve performance and reduce template rendering time. Precompiled templates compile the template code into an executable object and then use the object for rendering. Here is an example of a precompiled template:

First, we load the template file:

tmpl, err := template.ParseFiles("template.html")

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Then, we precompile:

tmpl, err := tmpl.ParseFiles("template.html")

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Finally, we can use precompile Template for rendering:

tmpl.Execute(w, data)

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By precompiling the template, we can avoid parsing the template file every time we render and improve performance.

Conclusion
In this article, we took an in-depth look at the use of Golang’s Template package and introduced some advanced techniques and optimization methods. By mastering these techniques, we can better use the Template package to generate and render text output. I hope this article can help you go from getting started to becoming proficient in the Template package, and give full play to its power in daily development.

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