1. 1. GOLANG TEMPLATEGOLANG TEMPLATE By, Karthick Kumar V
2. 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. 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. 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. 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. 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. 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 :

   Hello, {{.Text}}

   - It is similar to writing ERB in Ruby - Example :

   Hello,

8. 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. 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. 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. 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. 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. 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. 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. 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. 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.