Pretty command line apps with added JBang.
Following on from a previous post about Spring CLI and also Scripting I ventured further into the built-in https://www.jbang.dev/documentation/guide/latest/alias_catalogs.html in order to take a look into how others are putting together collections of JBang scripts.
What I discovered were a couple of references to some super helpful console UI libraries that work well with picocli and help you build more interactive and professional command line apps.
- https://github.com/awegmann/consoleui ( #ConsoleUI )
- https://github.com/vdmeer/asciitable ( #AsciiTable )
How to find other JBang scripts
The first catalog I looked at was from the JBang Github account - https://github.com/jbangdev/jbang-catalog.
JBang has commands to manage catalogs and to view the aliases that are imported from the named catalogs. In this case we can take a look at the aliases registered by the jbangdev catalog.
> jbang alias list jbangdev
bootstrap@jbangdev
Bootstrap a jbang script to make it self-contained.
https://github.com/jbangdev/jbang-catalog/blob/HEAD/bootstrap.java
bouncinglogo@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/bouncinglogo.java
catalog2readme@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/catalog2readme.java
dalle@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/dalle.java
ec@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/ec.jsh
env@jbangdev
Dump table of Environment Variables
https://github.com/jbangdev/jbang-catalog/blob/HEAD/env.java
faker@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/faker.jsh
gavsearch@jbangdev
`gavsearch` lets you use search.maven.org from command line.
Example: `gavsearch hibernate` will search for artifacts with hibernate in its name.
You can use any of the search modifiers search.maven.org supports, i.e.:
`gavsearch c:QuarkusTest` will search for artifacts with class `QuarkusTest`
https://github.com/jbangdev/jbang-catalog/blob/HEAD/gavsearch.java
getjava@jbangdev
Experimental utility to download Java distributions using api.foojay.io.
https://github.com/jbangdev/jbang-catalog/blob/HEAD/getjava.java
git@jbangdev
Git command line tool implemented with jgit. Lets you do basic git features without installing git!
https://github.com/jbangdev/jbang-catalog/blob/HEAD/jgit.java
h2@jbangdev
com.h2database:h2:1.4.200
Arguments: -webAllowOthers -tcpAllowOthers
hello@jbangdev
Script that says hello back for each argument
https://github.com/jbangdev/jbang-catalog/blob/HEAD/hello.java
httpd@jbangdev
`httpd` runs a webserver serving out the content of a directory.
Example: `jbang httpd@jbangdev -d _site` will serve out the `_site` folder on localhost:8000.
https://github.com/jbangdev/jbang-catalog/blob/HEAD/httpd.java
jmc@jbangdev
https://github.com/jbangdev/jbang-catalog/blob/HEAD/jmc.jsh
properties@jbangdev
Dump table of System properties
https://github.com/jbangdev/jbang-catalog/blob/HEAD/properties.java
Running the remote scripts via their alias can be done with the jbang command.
> jbang hello@jbangdev Robin
[jbang] Building jar for hello.java...
Hello Robin
ConsoleUI
The gavsearch@jbangdev script (https://github.com/jbangdev/jbang-catalog/blob/main/gavsearch.java) caught my eye as it uses some interaction in it’s prompt. When you type in the search terms, you get a list for selection. As a user you can use the up and down keys to move the cursor and enter to choose.
> jbang gavsearch@jbangdev hibernate
Searching for `hibernate` on search.maven.org...
[maven, gradle, jbang]
? coordinates
org.graceframework.plugins:hibernate:2023.2.0
com.github.houbb:hibernate:0.1.0
❯ io.github.qsy7.java.dependencies:hibernate:0.3.3
com.ksc.mission.base:hibernate:1.2.6.7
io.basc.framework:hibernate:1.8.3
com.github.davidmoten:hibernate:0.6
io.jstate:hibernate:0.0.2
org.lucee:hibernate:5.4.29.Final
com.gitlab.bessemer:hibernate:1.0.5
com.weicoder:hibernate:3.4.4.1
...
Searching for `hibernate` on search.maven.org...
[maven, gradle, jbang]
? coordinates hibernate:hibernate:3.1rc2
maven:
<dependency>
<groupId>hibernate</groupId>
<artifactId>hibernate</artifactId>
<version>3.1rc2</version>
</dependency>
gradle:
hibernate:hibernate:3.1rc2
jbang:
//DEPS hibernate:hibernate:3.1rc2
? Action
❯ Copy maven to Clipboard
Copy gradle to Clipboard
Copy jbang to Clipboard
Search older versions
Quit
This feature is pretty similar to the https://docs.spring.io/spring-shell/reference/components/ui/index.html I wrote about in the previous article. Looking at the script, we can see the dependency de.codeshelf.consoleui:consoleui:0.0.13 which is produced by the https://github.com/awegmann/consoleui project.
What does this look like when implementing?
> mkdir consoleuidemo && cd consoleuidemo
> jbang init --template=cli consoleuidemo.java
> jbang edit . consoleuidemo.java
Now we have a script ready to go, change the file to the following so that we have a script that demonstrates how to use the available prompt UI elements:
/// usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS info.picocli:picocli:4.6.3
//DEPS de.codeshelf.consoleui:consoleui:0.0.13
import de.codeshelf.consoleui.elements.ConfirmChoice;
import de.codeshelf.consoleui.elements.PromptableElementIF;
import de.codeshelf.consoleui.prompt.CheckboxResult;
import de.codeshelf.consoleui.prompt.ConfirmResult;
import de.codeshelf.consoleui.prompt.ConsolePrompt;
import de.codeshelf.consoleui.prompt.ExpandableChoiceResult;
import de.codeshelf.consoleui.prompt.InputResult;
import de.codeshelf.consoleui.prompt.ListResult;
import de.codeshelf.consoleui.prompt.PromtResultItemIF;
import jline.console.completer.FileNameCompleter;
import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Parameters;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.Callable;
import org.fusesource.jansi.AnsiConsole;
@Command(name = "consoleuidemo",
mixinStandardHelpOptions = true,
version = "consoleuidemo 0.1",
description = "consoleuidemo made with jbang")
class consoleuidemo implements Callable<Integer> {
public static void main( String... args ) {
int exitCode = new CommandLine( new consoleuidemo() ).execute( args );
System.exit( exitCode );
}
@Override
public Integer call() throws Exception { // your business logic goes here...
AnsiConsole.systemInstall();
ConsolePrompt prompt = new ConsolePrompt();
final List<PromptableElementIF> promptList = prompt.getPromptBuilder()
// check box prompt
.createCheckboxPrompt()
.name( "checkbox" )
.message( "Checkbox Prompt - Choose any number" )
.newItem()
.text( "Check 1" )
.name( "check-1-value" )
.add()
.newItem()
.text( "Check 2" )
.name( "check-2-value" )
.checked( true )
.add()
.addPrompt()
// choice prompt
.createChoicePrompt()
.name( "choice" )
.message( "Choice Prompt - Choose only one" )
.newItem()
.message( "Choice 1" )
.name( "choice-1-value" )
.key( '1' )
.asDefault()
.add()
.newItem()
.message( "Choice 2" )
.name( "choice-2-value" )
.key( '2' )
.add()
.addPrompt()
// confirm prompt
.createConfirmPromp()
.name( "confirm" )
.message( "Please confirm yes or no" )
.defaultValue( ConfirmChoice.ConfirmationValue.YES )
.addPrompt()
// input prompt
.createInputPrompt()
.name( "input" )
.message( "Enter a plain input" )
.defaultValue( "A default answer" )
.addPrompt()
// input prompt
.createInputPrompt()
.name( "passwd" )
.message( "Enter a masked password" )
.mask( '*' )
.addPrompt()
// input prompt
.createInputPrompt()
.name( "completed" )
.message( "Enter a completed value" )
.defaultValue( "A default answer" )
.addCompleter( new FileNameCompleter() )
.addPrompt()
// input prompt
.createListPrompt()
.name( "list" )
.message( "Choose one from the list" )
.newItem()
.text( "List Item 1" )
.name( "list-1-value" )
.add()
.newItem()
.text( "List Item 2" )
.name( "list-2-value" )
.add()
.addPrompt()
.build();
final HashMap<String, ? extends PromtResultItemIF> results = prompt.prompt( promptList );
final CheckboxResult checkbox = (CheckboxResult)results.get( "checkbox" );
System.out.printf( "checkbox %s%n", checkbox.getSelectedIds() );
final ExpandableChoiceResult choice = (ExpandableChoiceResult) results.get( "choice" );
System.out.printf( "choice %s%n", choice.getSelectedId() );
final ConfirmResult confirm = (ConfirmResult) results.get( "confirm" );
System.out.printf( "confirm %s%n", confirm.getConfirmed() );
final InputResult input = (InputResult) results.get( "input" );
System.out.printf( "input %s%n", input.getInput() );
final InputResult passwd = (InputResult) results.get( "passwd" );
System.out.printf( "passwd %s%n", passwd.getInput() );
final InputResult completed = (InputResult) results.get( "completed" );
System.out.printf( "completed %s%n", completed.getInput() );
final ListResult list = (ListResult) results.get( "list" );
System.out.printf( "list %s%n", list.getSelectedId() );
return 0;
}
}
Run the scripts and you be able to see each of the prompts in action.
> jbang consoleuidemo.java
[jbang] Building jar for consoleuidemo.java...
? Checkbox Prompt - Choose any number [check-2-value]
? Choice Prompt - Choose only one Choice 1
? Please confirm yes or no yes
? Enter a plain input A default answer
? Enter a masked password
? Enter a completed value A default answer
? Choose one from the list List Item 1
CheckboxResult{selectedIds=[check-2-value]}
ExpandableChoiceResult{selectedId='choice-1-value'}
ConfirmResult{confirmed=YES}
InputResult{input='A default answer'}
InputResult{input='null'}
InputResult{input='A default answer'}
ListResult{selectedId='list-1-value'}
And so thanks to this great little library we can add some great interactive prompts to our picocli command line.
AsciiTable
The env@jbangdev script was also interesting as the output from the command is a nicely formatted table.
> jbang env@jbangdev
┌────────────────────────┬─────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│Key │Value │
├────────────────────────┼─────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│COMMAND_MODE │unix2003 │
│GRADLE_HOME │/Users/robintegg/.sdkman/candidates/gradle/current │
│HOME │/Users/robintegg │
│HOMEBREW_CELLAR │/opt/homebrew/Cellar │
│HOMEBREW_PREFIX │/opt/homebrew │
│JAVA_HOME │/Users/robintegg/.sdkman/candidates/java/current │
│JBANG_HOME │/Users/robintegg/.sdkman/candidates/jbang/current │
│LANG │en_GB.UTF-8 │
│MAVEN_HOME │/Users/robintegg/.sdkman/candidates/maven/current │
│PWD │/Users/robintegg/spring-boot-cli │
│SHELL │/bin/zsh │
│USER │robintegg │
└────────────────────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
Taking a look at the source for this script we see a dependency on de.vandermeer:asciitable:0.3.2 which is a library from the https://github.com/vdmeer/asciitable project.
What does this look like when implementing?
> mkdir asciitabledemo && cd asciitable
> jbang init --template=cli asciitable.java
> jbang edit . asciitable.java
Now we have a script ready to go, change the file to the following so that we have a script that demonstrates how to use the available prompt table elements:
///usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS info.picocli:picocli:4.6.3
//DEPS de.vandermeer:asciitable:0.3.2
import de.vandermeer.asciitable.AsciiTable;
import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Parameters;
import java.util.concurrent.Callable;
@Command(name = "asciitable", mixinStandardHelpOptions = true, version = "asciitable 0.1",
description = "asciitable made with jbang")
class asciitable implements Callable<Integer> {
public static void main(String... args) {
int exitCode = new CommandLine(new asciitable()).execute(args);
System.exit(exitCode);
}
@Override
public Integer call() throws Exception { // your business logic goes here...
AsciiTable at = new AsciiTable();
at.addRule();
at.addRow("row 1 col 1", "row 1 col 2");
at.addRule();
at.addRow("row 2 col 1", "row 2 col 2");
at.addRule();
String rend = at.render();
System.out.println(rend);
return 0;
}
}
Run the scripts and you be able to see each of the table in action.
> jbang asciitable.java
[jbang] Building jar for asciitable.java...
┌───────────────────────────────────────┬──────────────────────────────────────┐
│row 1 col 1 │row 1 col 2 │
├───────────────────────────────────────┼──────────────────────────────────────┤
│row 2 col 1 │row 2 col 2 │
└───────────────────────────────────────┴──────────────────────────────────────┘
How sweet is that!