Templates are a way to merge generic text with more specific text Example : ERB / Haml – Template Engine for Ruby

1. GOLANG TEMPLATEGOLANG TEMPLATE
By,
Karthick Kumar V

2. Golang an OverviewGolang an Overview
● Go is a compiled language
● Its syntax loosely derived from C
● It is a fast-compiled, garbage-collected, concurrent
systems programming language
● It can compile a large project within a few seconds
● It is designed for multi-core computers

3. Template an OverviewTemplate an Overview
● Templates are a way to merge generic text with more
specific text
● Example : ERB / Haml – Template Engine for Ruby

4. Templating in GolangTemplating in Golang
● In Go Template Package is to handle Templating
● To rendering the output
● It has 2 types of Template Package
1. Text Template
- import “text/template”
2. HTML Template
- import “html/template”

5. Text Template PackageText Template Package
● Package Text template implements data-driven templates
for generating textual output
● It will not support generating HTML outputs
● Execution of the template is represented by a period '.' and
called "dot"

6. HTML Template PackageHTML Template Package
● Package HTML template implements data-driven
templates for generating HTML output safe against code
injection.
● It provides the same interface as package text/template
● This package wraps package text/template so you can
share its template API to parse and execute HTML
templates safely

7. Basic Syntax of TemplatingBasic Syntax of Templating
● Field substitution - {{.FieldName}}
- To include the content of a field within a template
- It is enclose within curly braces and add a dot at the
beginning
- Example : <p>Hello, {{.Text}}</P>
- It is similar to writing ERB in Ruby
- Example : <p>Hello, <%= @name %></p>

8. Basic Syntax of TemplatingBasic Syntax of Templating
● Nested fields - {{range}} and {{with}}
- Printing the output in Loop
- {{range}} just like range in Go
- {{with}} lets you write the same object name once and
use {{.}} as shorthand
● Pipeline - {{pipeline}}
- The default textual representation of the value of the
pipeline is copied to the output. Ex: {{. | html}}

9. Basic Syntax of TemplatingBasic Syntax of Templating
● Conditions – {{if}},{{else if}} and {{else}}
- To check for conditions in templates
- We can use the if-else syntax just like you do in regular
Go programs
- We cannot use conditional expressions in if, for
instance
- Example : {{.Mail}}=="atomic@gmail.com"
- Only boolean values are acceptable

10. Basic Syntax of TemplatingBasic Syntax of Templating
● Template variables - {{$variable}}
- To use local variables in templates
- We can use them with the with, range and if keywords
- their scope is between these keywords and {{end}}
- Example :
{{with $x := "output" | printf "%q"}}{{$x}}{{end}}

11. Basic Syntax of TemplatingBasic Syntax of Templating
● Nested templates - “Code Reusability”
- The templates can be reused across other templates
- like headers and footers of a blog
- We can declare header, content and footer as sub-
templates
- Example :
{{define "sub-template"}}content{{end}}

12. Basic Syntax of TemplatingBasic Syntax of Templating
● Must - “function”
- The template package has a function called Must
- It is used or validating templates, like the matching of
braces, comments, and variables
- Example :
template.Must(template.ParseFiles("index_temp.html")

13. Methods in TemplatingMethods in Templating
● To load the Template from a string or file and then perform
the merge
1. Parse
2. ParseFile
3. Execute
4. ExecuteTemplate
5. os.Stdout

14. Methods DescriptionMethods Description
● Parse
- It is used to render textual data
- Its is used in text/template
● ParseFile
- It is used to render HTML files
- It is used in html/template

15. Methods DescriptionMethods Description
● Execute
- It is used to display textual output
- Its is used in text/template
● ExecuteTemplate
- It is used to load HTML output
- It is used in html/template
● os.Stdout
- It is a standard output to print out the merged data

16. SummarySummary
● To combine dynamic data with templates using techniques
including printing data in loops, template functions and
nested templates
● The input text for a template is UTF-8-encoded text in any
format. "Actions" data evaluations or control structures are
delimited by "{{" and "}}"; all text outside actions is
copied to the output unchanged.