I have an annotated RepositoryRestResource for domain objects whose fields also contain binary data (images.) The Spring Rest machinery will create nice RESTful links for these fields, but I would also like to introduce a handler that returns the bare binary when browsers send an "image/*" accept header.
I could overlay a controller on the same paths, but it's brittle and I'd rather write a strategy class for this.
Possible? Any idea where to plug it in the Spring plumbing?
TIA,
Edoardo
Using the #RepositoryRestController annotation "properly", you should be able to restrict the controller override to the "image/*" only.
Say you have a simple domain object model (getters/setters and a some annotations omitted...)
public class Item {
#Id
private String id;
private String name;
}
Let's override the controller for image/* only
#RepositoryRestController
#ResponseBody
public class ItemRepositoryRestController {
#Autowired
private ItemRepository repository;
#RequestMapping(value = "/items/{id}", method = RequestMethod.GET,
produces = "image/*")
public Item getItem(#PathVariable(value = "id") String id)
{
Item item = repository.findOne(id);
/* do some magic with your item */
return item;
}
Obviously, no image/* data is returned here - you'll actually get a 400 error - but you do only get to this controller if asking if accepting image/*, while going through the automagic Spring Rest Controller when not asking for image/* if and only if you use #RequestMapping at the method level.
I haven't been to the point where I return raw binary data, you may have to use the HttpServletResponse directly as shown here. Or perhaps you already have an answer for this since in your comment you mention having added another resource path already (in which case I'm interested in how you return the raw data).
Related
I use the following command to generate a proxy class for a WCF service :
svcutil.exe" /out:C:\SomePath\.... /n:*,Internal.FooNameSpace
http://localhost/MyService.svc
The following class :
[ProtoContract]
[ServiceContract]
public class Foo
{
[ProtoMember(1)]
[DataMember(Order = 0)]
public string Bar { get; set; }
}
Becomes :
public partial class Foo : object, System.Runtime.Serialization.IExtensibleDataObject
{
private string BarField;
[System.Runtime.Serialization.DataMemberAttribute()]
public string Bar
{
get
{
return this.BarField;
}
set
{
this.BarField = value;
}
}
}
Is there a way to keep some specific attributes on the generated class ? (eg : ProtoMember in this case). I could off course hack the proxy but it create maintenance problems.
If you're adding that as a service reference, then nope: there's no way to retain that information - it simply isn't in the WCF endpoint.
IIRC, though, the WCF code-gen does actually come up with incremental Order values when you have multiple properties - i.e. the next property would be [System.Runtime.Serialization.DataMemberAttribute(Order = 1)], then 2 etc. So one option is to in a different file (the beauty of partial class), define (in the same namespace, etc) additional info about your type:
[ProtoContract(DataMemberOffset = 1)]
public partial class Foo { }
What this means is: when processing [DataMember], add 1 to every value - that means that you should get the required 1,2,3,4... and everything will be fine, and you haven't had to change the code.
Alternatively, you can be explicit:
[ProtoContract]
[ProtoPartialMember(1, nameof(Foo.Bar))]
[ProtoPartialMember(2, nameof(Foo.AnotherProp))]
public partial class Foo { }
This gives you a lot more flexibility to specify nuance about the properties.
As another alterative, you can configure everything at runtime:
RuntimeTypeModel.Default.Add(typeof(Foo), false)
.Add(1, nameof(Foo.Bar))
.Add(2, nameof(Foo.AnotherProp));
// or AddField to get the ValueMember that you can use to set
// fine-grained control
Finally, you can just ship the data contract dll, and tell svctil to use the types it already contains. You do this with the /reference:<file path> command-line switch, or there's a similar feature when using the UI tools (that lets you choose from the available dlls).
As a second "finally" (because one is not enough): you could describe the data instead as a .proto schema, and just tell the recipient to do the codegen locally and tell svcutil to exclude it (/excludeType: or /reference:). Note that the in progress rewrite of "protogen" does not currently include [DataContract]/[DataMember] attributes, but I could get that added today if it would be useful.
I have a abstract class and two implementations:
public abstract class Attribute {
// some properties
}
public class CustomAttribute extends Attribute{
private String property1;
}
public class DefaultAttribute extends Attribute{
private String property2;
}
There's another class, which includes these attributes:
public class Step{
private List<Attribute> attributes;
}
Now when Step gets serialized, the self link is missing. I need the self reference, since I want to update the attributes. According to the documentation, jackson needs a little help deciding which class to use. But that does not help, because I need to use both classes. So I build a custom serializer (and registered with a module) for Step and now I wonder how I can construct the link myself. I couldn't find anything in the Spring Data Rest docs regarding this. Since Spring Data Rest adds these links automatically, I think there might be a way to have the protocol/hostname/port information available in the JsonSerializer. How do I get the information in my custom serializer?
Ok, now I use the linkTo() function to get the hostname and port and I manually set the rest of the resource URL in my custom serializer.
final Link attributeLink = linkTo(CustomAttributeRepository.class)
.slash("/api")
.slash("customAttributes")
.slash(attribute.getIdentifier()).withSelfRel();
//#formatter:off
jsonGenerator.writeFieldName("_links");
jsonGenerator.writeStartObject();
jsonGenerator.writeFieldName("self");
jsonGenerator.writeStartObject();
jsonGenerator.writeStringField("href", attributeLink.getHref());
jsonGenerator.writeEndObject();
jsonGenerator.writeEndObject();
//#formatter:on
I'm setting a Property on Request.Properties inside a DelegatingHandler after I pluck some data out of a header on an incoming request to a Web API.
This all works fine. I can also access Request.Properties from within the controller as well as in my Action and Exception filters. However, I also need to access this data from outside of the controller (I call a business layer class from the controller). It is data I want to include in some logs in other places,
I can see HttpContext.Current from this class, and I can see the original header from here, so I guess I could pluck it out again, but since I have already done this and put it in the Properties it seems to make more sense to get it from there. However, I don't seem to have access to the Request.Properties from anywhere else.
If this isn't the right way to do this, how else would I pass around this per-request data so that it was accessible from anywhere on the stack in Web API?
I also need to access [Request.Properties] data from outside of the controller (I call a business layer class from the controller). It is data I want to include in some logs in other places... However, I don't seem to have access to the Request.Properties from anywhere else. If this isn't the right way to do this, how else would I pass around this per-request data so that it was accessible from anywhere on the stack in Web API?
You can get it from HttpContext.Current, though it is less than ideal. Keep in mind that if any other non-web applications consume the same business layer, then HttpContext.Current would be null. HttpContext.Current is only non-null when you are running in IIS, and an IIS thread is handling the execution of the request stack. If you ever plan to self-host the web api using OWIN without IIS, there will be no HttpContext.Current.
Personally, if the data really is important enough to be passed into the business layer to be logged, then I would just pass it to the business layer method:
public Task<HttpResponseMessage> SomeAction(SomeModel model) {
... other code
someBusinessLayerObject.SomeMethod(arg1, arg2, Request.Properties["myHeaderKey"]);
}
...If you need other values from Request.Properties, then you can just pass the whole dictionary to the methods that will end up using its values.
A third option if you are using an inversion of control container would be to add some kind of scoped object dependency class and put the data in there. Then constructor inject it into your business layer class:
public interface IHaveRequestData {
IDictionary<string, object> Properties { get; set; }
}
public class RequestData : IHaveRequestData {
public IDictionary<string, object> Properties { get; set; }
}
// ioc registration pseudocode
iocContainer.Register<IHaveRequestData, RequestData>(Lifetime
.WhateverYouNeedSoThatOneOfTheseGetsCreatedForEachWebRequest);
public class SomeController : ApiController {
private readonly IHaveRequestData RequestData;
public SomeController(IHaveRequestData requestData) {
RequestData = requestData;
}
public Task<HttpResponseMessage> SomeAction() {
// you may even be able to do this part in an action filter
RequestData.Properties = Request.Properties;
}
}
public class SomeBusinessLayerComponent {
private readonly IHaveRequestData RequestData;
private readonly ILog Log;
public SomeBusinessLayerComponent(IHaveRequestData requestData, ILog log) {
RequestData = requestData;
Log = log;
}
public Task SomeMethod() {
Log.Info(RequestData["myHeader"]);
}
}
In our project (springMVC) Rest API project I wish to only use ONE model for both request and response (to avoid having to add tons of code to copy field from object to object)
I'd like to use Swagger to handle all the doc, but I'm running into a little problem. For example let say I have a model User
public class User {
private Long id;
private String username;
private String password;
}
And a simple controller
public void createUser(#RequestBody User user)...
public User getUser(Long id) ..
Now I would like swagger to hide the property password on deserialization but not serialization (so having it display for the Input but the output)
and the opposite for the Id field.
I have tried using #JsonIgnore coupled with #JsonProperty but on the swagager-ui it either displays everything or hides everything. I cannot manage to it work.
Could someone indicate me what is the best way of archiving my goal ? Is it possible to use a single model for request and response while using swagger? In case it is not possible to use #JsonIgnore, is there a way to archive this differently ?
Swagger doesn't want you to have different input/output models with the same name. You should simply create an interface and attach that to the input, and for the output extend that interface or add an implementation with the additional field. For example, please see here for modeling tips:
https://swaggerhub.com/api/swagger-tutorials/modeling-samples/1.0.0
Your exact use case is one of them. The solution posted in the above link is here:
definitions:
User:
description: this is a user that would be passed into the system
properties:
username:
type: string
UserResponse:
allOf:
- $ref: '#/definitions/User'
- type: object
required:
- id
properties:
id:
type: string
format: uuid
readOnly: true
where User is the input object, and UserResponse is the output object, with the additional id field.
Add #JsonIgnore with getter of the field and #JsonProperty with the setter or with the field . As Due to use of immutable code or final fields sometime setter doesn't work.
example :
public class Student {
private Float name;
private String rollnum;
private String section;
#JsonProperty
private Boolean passOrFailed;
#JsonIgnore
public Boolean getpassOrFailed {
return active;
}
}
Remember to use both else else it will lead to removing element in deserialization
Say I am calling a third-party API which returns a Post, and I want to take that and transfer properties from it into my own Post class. I have in the past had a method like public static my.Post build(their.Post post) which maps the properties how I want.
However, is it better/valid to have a constructor that accepts their.Post and does the property mapping in there? Or should there always be a separate class that does the converting, and leaves my.Post in a more POJO state?
Thanks for your thoughts!
These answers always starts with "it depends."
People generally argue against using public static methods, based on the fact that it is hard to mock them (I don't buy into that bandwagon).
This comes down to design, do you want their post to be part of your class? If you add it as a "copy" constructor then it will now be part of your class and you are dependent on changes to post. If they change their post, your code has to adapt.
The better solution is to decouple it. You would need to find some extenal method to map the two. One way is to use a static builder method (like you mentioned) or if you want to take it a step further, a more complicated solution would be to extract the information you want from their post into some type of generic collection class. Then create a constructor that will accept that constructor class. This way if they change their design your class stays in tact and all you have to do is update the mappings from their post to your generic representation of it.
public class MyPost{
public MyPost(ICollectionOfProperties props){
//copy all properties.
}
}
public static class TheirPostExtensions{
public static ICollectionOfProperties ExtractProperties(this TheirPost thePost){
return new CollectionOfProperties(){
A = thePost.PropA,
B = thePost.PropB
};
}
}
public class Example{
public Example(){
TheirPost tp = new TheirPost();
ICollectionOfProperties props = tp.ExtractProperties();
MyPost mp = new MyPost(props);
}
}