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test page for Grails projects
Key Points
- Grails scaffolding and GORM is IBM i DFU on steroids - any database, any Java runtime environment
- Where it fits, Grails is the fastest way to build Web apps or microservices using the right templates
- Grails generated apps provide a good starting point to understand how Web and REST microservices are built
- Grails generates Spring Boot applications and REST services
- Grails can build traditional MVC web apps or REST microservices using templates and generators
- Grails can generate simple front-ends for REST microservices - Angular, React, Web
- Grails profiles define which options an application or service will use
- Grails uses Groovy - a Java superset and a dynamic JVM language
- Grails v4x will use Groovy v3x when available in 2020
- Groovy v3x will support latest Java versions ( Lamba expressions, modules etc )
- I should look at running Grails REST service in Docker container similar to a Spring Boot REST service
- Tracking Grails releases in Github ( milestones etc ) https://github.com/grails/grails-core/releases
References
Test References
Find grails scripts, files and apps
from ~/
Groovy, Grails scripts
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-rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//.gvm/grails/2.4.4/src/grails/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_dev/_gdev/bookstore/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_dev/_gdev/test2/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_dev/_gdev/gtest1/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_dev/qt1/grails-app/test1/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_dev/qt1/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 May 7 2016 .//.grails/wrapper/2.4.4/grails-2.4.4/src/grails/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_gd/_ptp/work/grails/_gdev/bookstore/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//_gd/_ptp/work/grails/_gdev/gtest1/grails-app/conf/spring/resources.groovy ==================== -rw-r--r-- 1 jimmason staff 84 Feb 21 2020 .//Google Drive/_work/learn/blearn-pc/grails/peblock/grails-app/conf/spring/resources.groovy.gz -rw-r--r-- 1 jimmason staff 84 Feb 21 2020 .//Google Drive/_work/learn/blearn-pc/grails/peblock/build/resources/main/spring/resources.groovy.gz ==================== -rw-r--r-- 1 jimmason staff 84 Sep 3 2018 .//Google Drive/_work/learn/blearn-pc/gtwf1/grails-app/conf/spring/resources.groovy.gz -rw-r--r-- 1 jimmason staff 84 Sep 3 2018 .//Google Drive/_work/learn/blearn-pc/gtwf1/build/resources/main/spring/resources.groovy.gz ==================== -rw-rw-r-- 1 jimmason staff 47 Feb 21 2020 .//Google Drive/_work/jim-acer/blearn/grails/peblock/grails-app/conf/spring/resources.groovy -rw-rw-r-- 1 jimmason staff 47 Feb 21 2020 .//Google Drive/_work/jim-acer/blearn/grails/peblock/build/resources/main/spring/resources.groovy -rw-rw-r-- 1 jimmason staff 47 Sep 3 2018 .//Google Drive/_work/jim-acer/blearn/gtwf1/grails-app/conf/spring/resources.groovy -rw-rw-r-- 1 jimmason staff 47 Sep 3 2018 .//Google Drive/_work/jim-acer/blearn/gtwf1/build/resources/main/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Google Drive/_ptp/work/grails/_gdev/bookstore/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Google Drive/_ptp/work/grails/_gdev/gtest1/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Feb 21 2015 .//Documents/_ptpdev/eclw2/qwpm/target/test-classes/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Documents/_ptpdev/eclw2/qwpm/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Documents/_ptpdev/eclw2/zdbmgt/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Documents/_ptpdev/eclw1/gttask1/grails-app/conf/spring/resources.groovy -rw-r--r-- 1 jimmason staff 47 Jul 30 2014 .//Documents/_ptpdev/eclw1/issdmg1/grails-app/conf/spring/resources.groovy |
gdrv files
gtwf1
gdrv//_work/learn/blearn-pc/gtwf1/grails-app/views/layouts/main.gsp.gz
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gdrv//_work/jim-acer/blearn/gtwf1/grails-app/init/gtwf1/BootStrap.groovy
MAC files
grails4
jim-macbook:_dev jimmason$ ls -l ~/_dev/grails4
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drwxr-xr-x 15 jimmason staff 480 May 7 2016 test2
udemy grails course test
gdrv//_work/jim-acer/blearn/grails/peblock/grails-app/controllers/peblock/UrlMappings.groovy
Grails Install
Grails Setup
cat ./setGrails4.sh
#!/bin/bash
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export CLASSPATH=$MYSQL_JDBC:$CLASSPATH
echo $PATH
Grails 3x requires JDK8 not JDK11
verify JDK is JDK8 NOT JDK11 ( the default system JDK I set )
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grails --version && groovy --version
Project References
Key Concepts
Grails 6.1.2 Guide
Grails 6.2.2 Documentation on Books and Authors Controllers - Quickstart Guide
Implement business logic in service classes with Controller classes only managing request flow
Services can have defined scopes
Domain classes as REST resources
Transactional annotations for transaction behavior required
n this example listBooks uses a read-only transaction, updateBook uses a default read-write transaction, and deleteBook is not transactional (probably not a good idea given its name).
https://docs.grails.org/6.1.2/guide/services.html
Multi-tenancy can be single database with discriminator column ( eg accountId ) or multi-database
https://guides.grails.org/discriminator-per-tenant/guide/index.html
https://guides.grails.org/database-per-tenant/guide/index.html
Build a Spring Boot application with Grails
Grails builds on Spring concepts
Scaffolding Views from Book class
Deploy as war or jar file
Grails Training
grails v4x books - authors 4 days
http://docs.grails.org/latest/
...
https://www.google.com/search?client=firefox-b-1-d&q=grails+version+4+tutorials
Grails and Okta
https://developer.okta.com/blog/2018/04/19/okta-with-grails
Grails CRUD app with Okta
https://developer.okta.com/blog/2018/06/04/okta-with-grails-part2
Grails with Spring Security - default
https://www.slideshare.net/JesusPerezFranco/spring-security-5?from_action=save
Grails download & install
http://grails.org/download.html
...
Manual Grails install
http://docs.grails.org/latest/guide/gettingStarted.html#downloadingAndInstalling
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On Unix/Linux based systems this is typically a matter of adding something like the following
export GRAILS_HOME=/path/to/grailsto your profile
Then add the bin directory to your PATH variable:
On Unix/Linux based systems this can be done by adding
export PATH="$PATH:$GRAILS_HOME/bin"to your profile
Run version check
- grails version
Create shell script to set Grails version
setGrails41.sh
export GRAILS_HOME=`/Library/Grails/grails-4.1.0.M1`
export PATH=$GRAILS_HOME/bin:$PATH
groovy -version
Grails beta versions
Check for Grails versions released in Github here ( including milestones ) - https://github.com/grails/grails-core/releases
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to validate, run:
grails -version
Grails docs on skwebteam
grails4-update-Slide_Deck_Introducing_Grails_4_Webinar.pdf
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grails-plugins.github.io-DB Reverse Engineering Plugin - Reference Documentation.pdf
Grails v4.0 Features
https://objectcomputing.com/products/grails/grails-roadmap
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- Groovy 2.5
- GORM 7.0 (Hibernate 5.2 minimum, Java 8 baseline)
- Java 8 Baseline
- Java 11 Support
- Spring 5.1
- Spring Boot 2.1
- Micronaut Integration
Grails JAX-RS plugin documentation ( for Grails v3x )
http://budjb.github.io/grails-jaxrs/3.x/latest/guide/introduction.html
...
It is targeted at developers who want to structure the web service layer of an application in a JSR 311 compatible way but still want to continue to use Grails' powerful features such as GORM, automated XML and JSON marshalling, Grails services, Grails filters and so on. This plugin is an alternative to Grails' built-in mechanism for implementing RESTful web services.
Features
- Makes the JSR 311 (JAX-RS) available to Grails applications for developing RESTful web services.
- New Grails artefact types, Resource and Provider, for JAX-RS classes.
- JAX-RS Resource classes under
grails-app/resourcesare auto-detected and can be modified at runtime. - JAX-RS Provider classes under
grails-app/providersare auto-detected and can be modified at runtime. - Extended Grails command line interface
- Create new resources and unit test templates via
grails create-resource <resource name>. - Generate ready-to-use resources from domain objects via
grails generate-resources <domain class name>. - Scaffolding
- Generate RESTful service interfaces for Grails domain objects.
- Content negotiation support for XML and JSON representations.
- Ability to use any Grails feature within JAX-RS resources and providers such as:
- GORM can be used for interacting with persistent domain objects.
- Grails filters for intercepting requests to JAX-RS resources. ( Deprecated )
- Grails services which can be auto-injected by name.
- Entity providers
- Domain object providers that convert between Grails domain objects and XML or JSON representations.
- Support classes for developing custom entity providers.
- Support for content negotiation based on the
Acceptrequest header. - Easy integration testing of JAX-RS resources and providers.
- Plugin users may choose between Jersey and Restlet as JAX-RS implementations by means of configuration.
- jaxrs applications can be deployed to Google App Engine (GAE).
Tutorial Migrate React Node.js app to Grails backend
https://guides.grails.org/grails-vs-nodejs/guide/index.html
...
You can go right to the completed example if you The completed sample project for this article can be found at: https://github.com/grails-guides/grails-vs-nodejs/tree/master/complete create react profile appEvery Grails project begins with a single Choose the latest version of Grails (3.3.0 as of the time of writing) and select the
start client and server appsOnce you’ve downloaded your application, expand it into a directory of your choice, gradle wrapper can eliminate need to install Grails locallyThe gradle is similar to npm for build management It doesn’t provide the CLI that npm offers but it fulfills a similar purpose in dependency management and build-processing. When a Gradle command (or "task") is run, Gradle will first download all dependencies listed in the project’s What about the When running a Gradle “task” from the project root directory, anything after |
Where does bootRun come from? This Gradle task is inherited from the Spring Boot framework, upon which Grails is based. Of course create-react-app projects don’t have such a task by default. The React profile provides the client:bootRun task as a wrapper around the npm/yarn start script. This allows you to use advanced Gradle features like running both server and client in parallel mode with one command. For developers, running ../gradlew client:bootRun is the same as running npm start (or yarn start) in a stock create-react-app project, and in fact you can run the client app exactly that way if you have npm/yarn installed on your machine.
Once the gradlew commands have completed downloading dependencies and launching their respective apps, you should be able to browse to http://localhost:8080 to see the Grails backend application, and http://localhost:3000 to view the React app.
Data source setup - postgresql
GORM - Grails Object Relational Management
http://gorm.grails.org/6.1.x/hibernate/manual/#quickStartGuide
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A domain class can be created with the create-domain-class command if you are using Grails, or if you are not using Grails you can just create the .groovy file manually:
grails create-domain-class helloworld.PersonThis will create a class at the location grails-app/domain/helloworld/Person.groovy such as the one below:
package helloworld
class Person {
}If you have the configured the dataSource.dbCreate property and set it to "update", "create" or "create-drop", GORM will automatically generate/modify the database tables for you. |
You can customize the class by adding properties:
class Person {
String name
Integer age
Date lastVisit
}Once you have a domain class try and manipulate it with console command in Grails by typing:
grails consoleThis loads an interactive GUI where you can run Groovy commands with access to the Spring ApplicationContext, GORM, etc.
Or if you are not using Grails here is a unit test template (using Spock) that can be run to test out the examples:
import spock.lang.*
import grails.gorm.annotation.Entity
import grails.transaction.Rollback
import org.grails.orm.hibernate.HibernateDatastore
import org.springframework.transaction.PlatformTransactionManager
class ExampleSpec extends Specification {
@Shared @AutoCleanup HibernateDatastore hibernateDatastore
@Shared PlatformTransactionManager transactionManager
void setupSpec() {
hibernateDatastore = new HibernateDatastore(Person)
transactionManager = hibernateDatastore.getTransactionManager()
}
@Rollback
void "test execute GORM standalone in a unit test"() {
// your logic here
}
}
@Entity
class Person {
...
}3.1. Basic CRUD
Try performing some basic CRUD (Create/Read/Update/Delete) operations.
3.1.1. Create
To create a domain class use Map constructor to set its properties and call the save() method:
def p = new Person(name: "Fred", age: 40, lastVisit: new Date())
p.save()The save() method will persist your class to the database using the underlying Hibernate ORM layer.
The save() method is defined by the GormEntity trait.
3.1.2. Read
GORM transparently adds an implicit id property to your domain class which you can use for retrieval:
def p = Person.get(1)
assert 1 == p.idThis uses the static get(id) method that expects a database identifier to read the Person object back from the database.
You can also load an object in a read-only state by using the read(id) method:
def p = Person.read(1)In this case the underlying Hibernate engine will not do any dirty checking and the object will not be persisted. Note that if you explicitly call the save() method then the object is placed back into a read-write state.
In addition, you can also load a proxy for an instance by using the load(id) method:
def p = Person.load(1)This incurs no database access until a method other than getId() is called. Hibernate then initializes the proxied instance, or throws an exception if no record is found for the specified id.
3.1.3. Update
To update an instance, change some properties and then call save() again:
def p = Person.get(1)
p.name = "Bob"
p.save()oks and authors tables - SQL
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create table author ( id bigint not auto_increment null, version bigint not null, name varchar(255) not null, email varchar(255) null, primary key (id)) ENGINE=InnoDB; create table book ( id bigint not auto_increment null, version bigint not null, title varchar(255) not null, type varchar(255), description varchar(2048), sold bigint null, primary key (id)) ENGINE=InnoDB; create table author_books ( author_id bigint not null, book_id bigint not null, primary key (author_id, book_id)) ENGINE=InnoDB; alter table author_books add index FKauthor_books_2_books (book_id), add constraint FKauthor_books_2_books foreign key (book_id) references book (id); alter table author_books add index FKauthor_books_2_authors (author_id), add constraint FKauthor_books_2_authors foreign key (author_id) references author(id); |
Books and authors output classes from DB plugin
| Code Block | ||||
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class Author {
String name
String email
String phone
static hasMany = [books: Book]
};
class Book {
String title
String publisher
BigDecimal price
String description
Integer quantitySold
static hasMany = [authors: Author]
static belongsTo = Author
};
class Author_Books {
String name
String email
static hasMany = [books: Book]
};
|
Final version of Books and authors output classes
Example of DB Reverse Engineering Output
Yes GORM. The reverse engineering for Grails is a little simpler because all that is needed are Domain classes and the framework handles all the hibernate mappings. So for example a DB table called Application would only need a single Domain class instead of a Domain, DAO and XML Mapping file. Here is an example with one-to-many and many-to-one relationships
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Golang GORM
GORM - create tables from GOR
...
go get -u github.com/jinzhu/gormsimple crud example
package main
import (
"github.com/jinzhu/gorm"
_ "github.com/jinzhu/gorm/dialects/sqlite"
)
type Product struct {
gorm.Model
Code string
Price uint
}
func main() {
db, err := gorm.Open("sqlite3", "test.db")
if err != nil {
panic("failed to connect database")
}
defer db.Close()
// Migrate the schema
db.AutoMigrate(&Product{})
// Create
db.Create(&Product{Code: "L1212", Price: 1000})
// Read
var product Product
db.First(&product, 1) // find product with id 1
db.First(&product, "code = ?", "L1212") // find product with code l1212
// Update - update product's price to 2000
db.Model(&product).Update("Price", 2000)
// Delete - delete product
db.Delete(&product)
}Generate Golang structs from SQL databases
https://github.com/smallnest/gen
...
- no external dependencies
- could extend to NoSQL
- can pickup reference relations as "has" or "owns"
- can pickup primary key
Grails with Groovy 3x
4.1 M builds use Groovy 3
https://github.com/grails/grails-core/releases/tag/v4.1.0.M1
Potential Value Opportunities
Potential Challenges
Grails Java JDK compatibility
At some later point, ( 2020 or ? ), Grails will catch up with supported Java JDKs but not now.
...
Groovy 2x still works with JDK 8 ( used by Grails 4x ) but not JDK 11 without a lot of custom work.
Grails 4 upgrade issues related to Java etc
https://github.com/grails/grails-core/wiki/Grails-4-Upgrade
Bug> Grails console can't open groovy file from menu or cli
bug> can't open a file from grails console using the file menu
workaround> use CTL + O
- open groovyconsole normally
- use CTL + O to open file selector window
- select a groovy file
- press Enter
- << file opens normally in groovy console
...
option 2> manually copy file contents to console window
open grails console
open the file from the File menu ( nothing shows )
open the same groovy file in another text editor
copy and paste the entire contents to the console window
add a comment line
File > save
check the saved file in the text editor to see the comment line exists
Grails 4.1 M++ – Groovy 3 and JDK11
Candidate Solutions
SWT Grails Books and Authors Lab - 2009 - V2X
<< see the pdf for the images >>
...
Congratulations – you've built a Web database application in 1 hour!
Simple Grails CRUD app on Grails 2x
User
EBC
Account
Device
Location
Energy
Steps after Grails setup
grails createApp gtcrud1
...
- add the application folder to the grails path in the console
Step-by-step guide for Example
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Recommended Next Steps
Related articles
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