Skip to content

Latest commit

 

History

History
198 lines (151 loc) · 4.76 KB

README.adoc

File metadata and controls

198 lines (151 loc) · 4.76 KB

Doctors

Status

Travis C/I Project Health - Build Status (Travis CI)

Notes About Doctor

A Groovy Template Engine to produce html stream from text files written in the Asciidoctor syntax.

Using Groovlets - a nice explanation HOW-TO

Web.xml
<!-- setup the GroovyServlet in your web.xml
          and bind the script file extension -->

  <servlet>
      <servlet-name>groovlets</servlet-name>
      <servlet-class>groovy.servlet.GroovyServlet</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>groovlets</servlet-name>
      <url-pattern>*.groovy</url-pattern>
  </servlet-mapping>
Build.gradle script
 apply plugin: 'groovy' // java is ok too
  apply plugin: 'war'

  repositories {
    mavenCentral()
    mavenLocal()
  }

  dependencies {
    providedCompile 'javax.servlet:servlet-api:2.5'
    compile 'org.codehaus.groovy:groovy-all:2.4.5'
  }

Handle a GET

Output HTML on GET request is pretty easy using the built-in MarkupBuilder

Template script
// if present use name parameter from
// query string (eg. ?name=Francesco)
// else use "World"

def name = params.name ?: "World"

// output some html

html.html {
    head {
        title "Hello from Groovlet!"
    }
    body {
        h1 "Hello, ${name}!"
    }
}

In the example above, you see also Groovy native template engine: (G)String concatenation.

Handle a POST

With built-in variables bound from the Servlet request via the GrailsServlet, you can also perform more complicated operations like handling some JSON in POST request.

Groovy Request Handler script
response.contentType = 'application/json'

// Access headers, with context bound variable
if (headers['Content-Type'] != "application/json") {
    throw new RuntimeException("Please use 'application/json' header")
}

// Get content from POST body
def jsonContent = request.reader.text

// Parse JSON to Map
def content = null
if (jsonContent) {
    content = new JsonSlurper()
                .parseText(jsonContent)
}

// build JSON output
json."echo" {
    "original" content
}

Groovy Template Servlet

It delegates work to a groovy.text.TemplateEngine implementation processing HTTP requests.

Usage

helloworld.html is a headless HTML-like template

Groovy Template script
  <html>
    <body>
      <% 3.times { %>
        Hello World!
      <% } %>
      <br>
    </body>
  </html>

Minimal web.xml example serving HTML-like templates

Web.xml
 <web-app>
   <servlet>
     <servlet-name>template</servlet-name>
     <servlet-class>groovy.servlet.TemplateServlet</servlet-class>
   </servlet>
   <servlet-mapping>
     <servlet-name>template</servlet-name>
     <url-pattern>*.html</url-pattern>
   </servlet-mapping>
 </web-app>

Template Engine Configuration

By default, the TemplateServlet uses the SimpleTemplateEngine which interprets JSP-like templates. The init parameter template.engine defines the fully qualified class name of the template to use:

  1. template.engine = [empty] - equals groovy.text.SimpleTemplateEngine

  2. template.engine = groovy.text.SimpleTemplateEngine

  3. template.engine = groovy.text.GStringTemplateEngine

  4. template.engine = groovy.text.XmlTemplateEngine

  5. template.engine = groovy.text.DoctorTemplateEngine

Additional Web.xml configuration when serving Asciidcotor templates

web.xml
        <servlet>
		<servlet-name>DoctorTemplateServlet</servlet-name>
		<servlet-class>groovyx.caelyf.CaelyfTemplateServlet</servlet-class>
 		<init-param>
			<param-name>template.engine</param-name>
			<param-value>groovy.text.DoctorTemplateEngine</param-value>
		</init-param>
        <init-param>
            <!-- Remove the default "generated by" messages from the templates -->
            <param-name>generated.by</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>verbose</param-name>
            <!-- Output generation time in the HTML, see source page -->
            <param-value>true</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
	</servlet>

    <servlet-mapping>
        <servlet-name>DoctorTemplateServlet</servlet-name>
        <url-pattern>*.adoc</url-pattern>
    </servlet-mapping>
Tip
 Set <load-on-startup> parameter to zero to improve initial performance or if asciidoctor files are not used immediately