I have data writing to a mongoDB database with issues using integration tests and the Grails scaffolding. When trying to select a domain instance from the 'list' type page, I get the error "[domain name] not found with id null".
I am sure it is because of the Grails url [controller]/[action]/[id]. This id is a string and needs to be converted to an ObjectId for Grails queries.
Is there a way to do this so that it affects a specified domain or even better yet, all of the domains at once?
I guess as I'm writing my app, I can convert it to an ObjectId from within the action method, but I'd like to have the scaffolding work or provide a global solution.
I believe this is happening because the show() method (that the Grails scaffolding functionality generates as an action) accepts an id parameter of type Long ie.
def show(Long id) {
def suiteInstance = Suite.get(id)
if (!suiteInstance) {
flash.message = message(code: 'default.not.found.message', args: [message(code: 'suite.label', default: 'MyDomainClass'), id])
redirect(action: "list")
return
}
[suiteInstance: suiteInstance]
}
which binds the id parameter to the argument. Because the ObjectId can't be converted to a Long, it ends up being null, hence the call to MyDomainClass.get(id) fails with the error message.
You can get around this by overriding the show() action in your scaffolded controller so that it expects an ObjectId or String, but I would say the proper fix for this is to update the Grails scaffolding plugin so it is a little more liberal in the types of IDs it accepts.
I had this problem as well. You can keep the domain object id as an ObjectId and update the controller as follows:
domain Object:
import org.bson.types.ObjectId;
class DomainObject {
ObjectId id
// Add other member variables...
}
Controller:
def show(String id) {
def domainObjectInstance = domainObject.get(new ObjectId(id))
if (!domainObjectInstance) {
flash.message = message(code: 'default.not.found.message', args: [message(code: 'domainObject.label', default: 'DomainObject'), id])
redirect(action: "list")
return
}
[domainObjectInstance: domainObjectInstance]
}
You would also need to update your other controller methods that use id as well such as edit, update etc.
Additionally, if you want the grails default controller generation to work like this for all your domain objects you can update the template as coderLMN suggests.
The get(params.id) call in show() method will NOT convert params.id String to an ObjectId object, so the domain instance will be null, then the following code takes you to list action with an error message:
if (!exampleInstance) {
flash.message = message(code: 'default.not.found.message', args: [message(code: 'example.label', default: 'Example'), params.id])
redirect(action: "list")
return
}
Possible solutions:
you can run "grails install-template" command, so that the scaffolding templates in src/templates/scaffolding/ directory can be modified. Then you have new scaffold ready to generate customized controllers, views, tests for all your Domain classes.
A simpler solution is to define the id property as String instead of ObjectId. A String id will be equal to objectId.toString(), in this case your scaffold will work.
In domain classes keep you id type as ObjectId and keep scaffold = true for all respective controllers.
In Domain class :
ObjectId id
In respective controller :
static scaffold = true
Clear all existing collections from Mongo
I guess that's sufficient to have Grails-Mongo app up & running, considering you have correctly configured mongo-plugin
Related
I am working on a simple Finatra API example, but having trouble using a case class for the POST request when using more than one field in the request body.
Here is an example of my case class and controller:
class SaleResource extends Controller {
post("/sales") { sale: Sale =>
s"$sale"
}
}
case class Sale(
user: Option[String],
streetAddress: Option[String]
)
I send a post request to that route with the following request body JSON:
{
"user": "Foo Barrington",
"streetAddress":"Baz Street"
}
The response:
Sale(Some(Foo Barrington),None)
The response shows that the user is being properly deserialized, but for some reason I cannot get the streetAddress field to populate.
Also, I noticed when I set either of these fields to String instead of Option[String] I only get unsuccessful 500 responses.
Things I have tried:
case statements matching Some(streetAddress) to that fields string value or "none found" when it is None. In these cases it still is saying streetAddress is None when it is not.
Making the request with both curl and Postman.
I can always access the user field from the Sales object, but never the streetAddress (or any other field from the request body for that matter if I add test elements to the case class.
I would expect both fields to be recognized since they are both provided in the request. I am newer to Scala/Finatra in general, so it is possible I am just using the Finatra library or Case classes incorrectly.
EDIT:
It seems as if changing the field names to not be mixed/camelcase fixes all issues, but this seems like odd behavior.
Finatra uses Jackson library behind the scenes. The default configuration uses PropertyNamingStrategy.SNAKE_CASE which seems like:
{
"user": "Foo Barrington",
"street_address":"Baz Street"
}
You need to change it to PropertyNamingStrategy.LOWER_CAMEL_CASE to parse that JSON.
In order to do that, you need to define a custom FinatraJacksonModule and tell the app to
use it.
object CustomFinatraJacksonModule extends FinatraJacksonModule {
override val propertyNamingStrategy = PropertyNamingStrategy.LOWER_CAMEL_CASE
}
class MyFinatraHttpServer extends HttpServer {
override protected def jacksonModule: Module = CustomFinatraJacksonModule
}
Jackson Integration provides more information about the topic.
Using Grails 3.1.3, I created a rest-api so that I am able to capture GET requests that not only query for one parameter, but multiple if needed. I don't know how to code this correctly inside the UrlMappings file. Here are the details.
Domain class:
class ProdDetail {
Integer pid
String title
String category
Integer year
}
And some of these inside the BootStrap:
new ProdDetail(pid:'101', title:'No Highway', author:'Nevil Shute', category:'fiction', year:1948).save(failOnError:true)
new ProdDetail(pid:'214', title:'In the Country of Men', author:'Hisham Matar', category:'misery', year:2007).save(failOnError:true)
Controller:
protected List<ProdDetail> listAllResources(Map params) {
println params
try {
ProdDetail.where {
if (params.category && params.maxYear) {
category == params.category && year <= params.int('maxYear')
} else if (params.category) {
category == params.category
} else if (params.maxYear) {
year <= params.int('maxYear')
} else {
pid > 0
}
}.list()
} catch (Exception e) {
[]
}
}
UrlMappings:
static mappings = {
"/prodDetails"(resources:'prodDetail')
"/prodDetails/category/$category?"(controller:'prodDetail', action:'index')
"/prodDetails/yearUnder/$maxYear?"(controller:'prodDetail', action:'index')
// the line below is not right I think, what's the correct format?
"/prodDetails/combo/$category?&$maxYear?"(controller:'prodDetail', action:'index')
}
Now, where as these two curls would work:
curl localhost:8080/prodDetails/category/misery
curl localhost:8080/prodDetails/yearUnder/2007
This one fails to go into the desired clause in the controller to detect both params:
curl localhost:8080/prodDetails/combo/?category=misery&maxYear=2007
It just detects 'category' but not the 'maxYear' which it considers as 'null'.
How can I cater for such a curl please?
It kind of depends on what you want your URLs to look like, but assuming you want your requests to look like this:
http://localhost:8080/prodDetails/combo/misery?maxYear=2007&title=common
The UrlMappings should look like
static mappings = {
"/prodDetails/combo/$category"(controller:'prodDetail', action:'index')
}
Then the params object in the controller should have both whatever's in the place of $category, in this example misery, and the other parameters after the ? as well.
If you want the parameters to be in the path you can do this:
static mappings = {
"/prodDetails/combo/$category/$title/$maxYear"(controller:'prodDetail', action:'index')
}
And the request would then be:
http://localhost:8080/prodDetails/combo/misery/common/2007
One other option would be to use a command object. So if you had:
static mappings = {
"/prodDetails/combosearch"(controller:'prodDetail', action:'comboSearch')
}
And then created an object beside the controller called ComboSearchCommand.groovy that looked like:
import grails.validation.Validateable
class ComboSearchCommand implements Validetable {
String category
String title
int maxYear
static constraints = {
category blank: false, nullable: true
title blank: false, nullable: true
maxYear blank: false, nullable: true
}
}
(Which you can do validation on just like a domain object)
And then in your controller you have the method take the command object instead of params
protected List<ProdDetail> comboSearch(ComboSearchCommand command) {
println command.category
}
Then your URL would be
http://localhost:8080/prodDetails/combosearch?category=misery&maxYear=2007&title=common
And the parameters will bind to the command object.
I've used that quite a bit, you can share validations or have your command object inherit validations from domain objects, lots of flexibility.
https://grails.github.io/grails-doc/latest/guide/single.html#commandObjects
You don't need to specify the parameters in UrlMappings if those params are not part of the URL:
No need of this:
"/prodDetails/combo/$category&?$maxYear?"(controller:'prodDetail', action:'index')
Yes you need this to match the URL to a controller/action (but remove the ?)
"/prodDetails/yearUnder/$maxYear?"(controller:'prodDetail', action:'index')
Also, you don't need Map params in listAllResources(Map params)
"params" is an injected property of controllers, the println params will work OK with: listAllResources()
What I would do is to define:
listAllResources(String category, int maxYear, ...) where ... are all the params that action can receive, most would be optional, so you will receive a null value if not included in your request.
Remember: UrlMappings are to map URLs to controller/actions, and you have the same controller/action, so I would remove all the mappings and process the optional parameters in the action just checking which are null or not.
Edit (considering comments)
Q: the method is not overloaded to handle params like that
A: methods are dynamic, this is Grails / Groovy, not Java. It will call the action method even if all the params are null. I would recommend you to go through the Grails controller documentation in detail.
Q: found that the listAllResources method was never called
A: remove the protected keyword from the action, only subclasses would be able to invoke that method. Also, you can add an UrlMapping to avoid users to invoke that URL (match the URL and return 404 Not Available or something like that)
Q: I want to handle a GET request like this localhost:8080/prodDetails/combo?category=misery&year=2016&title=commonTitle, how exactly should the i) entry in UrlMappings, and ii) the listAllResources method look like?
A:
static mappings = {
// if "compo" comes in the action portion, map that to the listAllResources method
// as I said, if all parameters comes in the query string, no further actions are needed, if you need parameters to be part of the URL path, then you need to play with the $xxxx in the URL
"/prodDetails/combo"(controller:'prodDetail', action:'listAllResources')
}
def listAllResources()
{
println params
// logic here
render "OK"
}
Check:
https://grails.github.io/grails-doc/latest/ref/Controllers/params.html
https://grails.github.io/grails-doc/latest/ref/Controllers/render.html
How does grails pass arguments to controller methods?
A question about rest url mappings.. I would like to use a different id in the rest calls then the database id.
Lets say i have an url mapping like this:
"/books"(resources:"book")
Then the show action would be..
def show(Book book) {
if(book == null) {
render status:404
}
else {
return [book: book]
}
}
This would load the book belonging the the id that was passed in via the rest call like: http://url/books/1
If i want to use a different property of the class Book how would i get the automatic databind working? Assume that my book also has a uuid.
How do i get http://url/books/4860ca28-9a76-480f-b898-fffedda1888f to work in the same way as the database id?
Simplest example of this, I get a collection and try to output it via Web API:
// GET api/items
public IEnumerable<Item> Get()
{
return MyContext.Items.ToList();
}
And I get the error:
Object of type
'System.Data.Objects.ObjectQuery`1[Dcip.Ams.BO.EquipmentWarranty]'
cannot be converted to type
'System.Data.Entity.DbSet`1[Dcip.Ams.BO.EquipmentWarranty]'
This is a pretty common error to do with the new proxies, and I know that I can fix it by setting:
MyContext.Configuration.ProxyCreationEnabled = false;
But that defeats the purpose of a lot of what I am trying to do. Is there a better way?
I would suggest Disable Proxy Creation only in the place where you don't need or is causing you trouble. You don't have to disable it globally you can just disable the current DB context via code...
[HttpGet]
[WithDbContextApi]
public HttpResponseMessage Get(int take = 10, int skip = 0)
{
CurrentDbContext.Configuration.ProxyCreationEnabled = false;
var lista = CurrentDbContext.PaymentTypes
.OrderByDescending(x => x.Id)
.Skip(skip)
.Take(take)
.ToList();
var count = CurrentDbContext.PaymentTypes.Count();
return Request.CreateResponse(HttpStatusCode.OK, new { PaymentTypes = lista, TotalCount = count });
}
Here I only disabled the ProxyCreation in this method, because for every request there is a new DBContext created and therefore I only disabled the ProxyCreation for this case .
Hope it helps
if you have navigation properties and you do not want make them non virtual, you should using JSON.NET and change configuration in App_Start to using JSON not XML!
after install JSON.NET From NuGet, insert this code in WebApiConfig.cs in Register method
var json = config.Formatters.JsonFormatter;
json.SerializerSettings.PreserveReferencesHandling = Newtonsoft.Json.PreserveReferencesHandling.Objects;
config.Formatters.Remove(config.Formatters.XmlFormatter);
If you have navigation properties make them non virtual. Mapping will still work but it prevents the creation of Dynamic Proxy entities which cannot be serialized.]
Not having lazy loading is fine in a WebApi as you don't have a persistent connection and you ran a .ToList() anyway.
I just disabled proxy classes on a per needed basis:
// GET: ALL Employee
public IEnumerable<DimEmployee> Get()
{
using (AdventureWorks_MBDEV_DW2008Entities entities = new AdventureWorks_MBDEV_DW2008Entities())
{
entities.Configuration.ProxyCreationEnabled = false;
return entities.DimEmployees.ToList();
}
}
Add the following code in Application_Start function of Global.asax.cs:
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings
.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
GlobalConfiguration.Configuration.Formatters
.Remove(GlobalConfiguration.Configuration.Formatters.XmlFormatter);
This instruct the API to serialize every response into JSON and remove XML responses.
In my case the object being returned had a property within it with a type that did not have an argumentless/default constructor. By adding a zero-argument constructor to that type the object could be serialized successfully.
I had the same problem and my DTO was missing an parameter less constructor.
public UserVM() { }
public UserVM(User U)
{
LoginId = U.LoginId;
GroupName = U.GroupName;
}
First constructor was missing.
I got this error message and it turns out the problem was that I had accidentally set my class to use the same serialized property name for two properties:
public class ResultDto
{
//...
[JsonProperty(PropertyName="DataCheckedBy")]
public string ActualAssociations { get; set; }
[JsonProperty(PropertyName="DataCheckedBy")]
public string ExpectedAssociations { get; set; }
//...
}
If you're getting this error and you aren't sending entities directly through your API, copy the class that's failing to serialize to LINQPad and just call JsonConvert.SerializeObject() on it and it should give you a better error message than this crap. As soon as I tried this it gave me the following error message: A member with the name 'DataCheckedBy' already exists on 'UserQuery+ResultDto'. Use the JsonPropertyAttribute to specify another name.
After disable Proxy Creation, use eager loading (Include()) to load the proxy object.
In my Project EntityCollection returned from the WebApi action method.
Configuration.ProxyCreationEnabled = false not applicable. I have tried the below approach it is working fine for me.
Control Panel.
2.Turn on Windows Features on or off
Choose Internet Information Service
Check all the World Wide Web Components it would be better to check all the components in IIS.
Install the components.
Go to (IIS) type inetmgr in command prompt.
select the published code in the Virtual directory.
Convert into application
Browse it the application.
The answer by #Mahdi perfectly fixes the issue for me, however what I noticed is that if my Newtonsoft.JSON is 11.0 version then it doesn't fix the issue, but the moment I update Newtonsoft.JSON to latest 13.0 it starts working.
I'm trying to load employees using Entity Framework.
The method is supposed to return employee list.
It' s giving this error:
Cannot implicit convert....<Class names and methods>.... An Explicit conversion exists.
I think the problem is related to casting.
Please check below code.
public List<Employee> LoadEmployees()
{
try
{
EMployeeDB1Entities EE = new EMployeeDB1Entities();
var Employees = EE.Employees.Where(p => p.Name.StartsWith("T"));
return Employees;
}
catch
{
return null;
}
}
var Employees = EE.Employees.Where(p => p.Name.StartsWith("T")).ToList();
Update your code to:
return Employees.ToList();
Also do note that this is the ToList() method that actually triggers the database query.
EE.Employees.Where(....) doesn't query the database. The DB is queried when the result of the Where() is enumerated, which is what .ToList() does.
Thanks it works...one more issue, suppose if I want to bind above list
to grid then how can I bind ?
Assuming you're using WPF or Silverlight:
To bind the result of your query on a datagrid, you could expose a public property of type ObservableCollection.
This collection accepts an IEnumerable<T> object as constructor.
You can write:
var myCollection = new ObservableCollection<Employee>(this.LoadEmployees());
Then bind the ItemSource property of your datagrid to your collection.
If you have more problems using bindings, I recommend you to ask another question, because the subject is quite different.