Can API-Gateway check the input parameters and reject (without passing it to Lambda) an HTTP request? - aws-lambda

I would like to use API-Gateway (plus Lambda) to realize a PetStore Restful API. One of the API entry point is and the body of the POST request needs to contain 'name'. See the PetStore definition snippet below:
/pets/
POST
definitions:
NewPet:
required:
- name
properties:
name:
type: string
tag:
type: string
Can I make API-Gateway smart enough to reject requests that does not contain the required field (in this case, 'name'), without calling the Lambda (yes, I understand I am able to check the input fields inside the Lambda function, but I wonder if I can avoid it)? -- this would save a lot of time and complexity to deal with the corner case.

This can be achieved through using request validation set in the "method request" settings.

If you want to validate the request body rather than query string you need to create a model;
APIs > {ApiName} > Models
In the sidebar.
Create your model using JSON Schema
In the API Gateway, choose to validate the request body then select your created model in the dropdown.
API Gateway config page

Related

Angular $http.delete request with body

So I looked at this post:
is an entity body allowed for an http delete request
Which seems to indicate that while it is 'ok' to do on some conceptual level, in practice it may not be doable because browsers just ignore it.
I have some express.js authentication middleware I need to get through, and I don't want to attach my user details to url params. All my other requests that need to authenticate attach these details to the body of the request.
Is there some way to force this? I saw some other posts where some people seemed to have success in passing a body with their delete request.
I am running a node/sails back-end. It always logs the body as undefined for a delete request. Is there any way to modify
The sails API pulls the id of the object to delete from the params, so we have to append the id to the url.
But if I want to pass some authentication details in a body for server-side verification before processing the delete request, I can't just stick them in an object as the second parameter of the delete request, like you can with $http.post.
Angular's post method automatically assigns whatever we insert as a second parameter to the body of the request, but the delete method does not.
Angular's $http.delete method does allow us to supply a config object as the second parameter, through which we can get access to the 'data' property. This is the same way post does it through it's second parameter.
So if we need to attach a body to a delete request we can use the following:
$http.delete('/api/' + objectToDelete.id, {data: {id: currentUser().id, level: currentUser().level}});
This will pass the object to delete's id in the url parameter, and my user credentials in the body as an object.
Honestly, everytime a trouble sounds like a "restriction of as REST", a rethink of the strategy and the philosophy might be a good idea.
I have some authentication middleware I need to get through
I don't want to attach my user details to url params
I'm not directly answering the question, but you should know that among the commons
URL parameters (or query, but URL anyway)
Body
there is a third option for "passing values to the server" :
request Headers
I'd just suggest to consider that third option to provide your credentials: request header.
Edit : following appendix would just apply to any "external" middleware, like a proxy server or whatever, not a true express middleware inside sails.js
In addition, that would be a good idea that your middleware stripped those headers before redirecting to the real action.

Web API ignores non-model body parameters; should throw error

In Web API v2 when you supply data in the POST body that are not part of the model, they are ignored by the framework. This is fine in most cases, but I need to check this and return an error response, so the user doesn't get unexpected results (he expects these wrong parameters to do something...).
So how do I check for this? The model will be null, but when the framework has parsed the data and returned a null-model, I can no longer access the body through Request.Content. So what options are there?
One way is to derive your DTO class from DynamicObject. Check out my blog post: http://lbadri.wordpress.com/2014/01/28/detecting-extra-fields-in-asp-net-web-api-request/

RESTful api for dynamic showform on top of spring mvc

I want to build a typical mvc app for CRUD of simple items, the api s should be RESTful. The catch here is, that i have a large pallete of items that needs to be initialized. On the server side those items are defined as java beans and the corresponding create form for the item is dynamically created from the field information(data type, validation constraints etc) harvested from the bean.
I am new to REST and just read up about how the urls should be nouns defining the resource and action specified by HTTP verb. In that perspective how to model something like
.../client/showForm?type=xyz from non RESTful way to RESTful one ?? My intention here is to tell the server to dynamically construct and send back a CREATE form for client of type xyz. The obvious problem with url i mentioned above is that it specifies action in the url which, from what i have read, makes it non RESTful.
When I think of REST, I think of resources. I think of data. In other words, I don't think of REST as being something that I would typically use to retrieve a form, which is a user interface component.
REST is an architectural style that is used to identify a resource on a server using a uniform resource identifier, or URI. Additionally, actions performed on those resources identified by the URI are determined based on the specific HTTP Method used in the request: GET, POST, PUT, DELETE, etc.
Thus, let's say you have a Client object. That client object might have the following properties:
Name
Location
AccountNumber
If I wanted to retrieve the data for a single client, I might use the following URI:
GET /client/xyz/ # xyx is the accountnumber used to identify the client.
I would use a GET method, since REST describes GET as being the method to use when retrieving data from the server.
The data could theoretically be returned in HTML, since REST is not a standard but more like a series of flexible guidelines; however, to really decouple my data from my user interface, I would choose to use something platform independent like JSON or XML to represent the data.
Next, when adding a client to the collection on the server, I would use the /client/ URI pattern, but I would use the HTTP Method POST, which is used when adding a resource to a collection on the server.
# Pass the data as JSON to the server and tell the server to add the client to the
# collection
POST /client/ {"accountnumber":"abc" , "Name" : "Jones" , "Location" : "Florida"}
If I were to modify an existing record on the server or replace it, I would most likely use the HTTP Method PUT, since REST guidelines say that PUT should be used if repeating the same operation repeatedly would not change the state of the server.
# Replace the client abc with a new resource
PUT /client/abc/ {"accountnumber":"abc" , "Name" : "Bob Jones" , "Location" : "Florida"}
The general idea behind REST is that it is used to identify a resource and then take action on that resource based on what HTTP Method is used.
If you insist on coupling your data with your view, one way accomplish this and retrieve the actual form, with the client data, could be to represent the form as a resource itself:
GET /client/abc/htmlform/
This URL would of course return your client data for client abc, but in an HTML form that would be rendered by the browser.
While my style of coding utilizes data transports such as JSON or XML to abstract and separate my data from my view, you could very well transport that data as HTML. However, the advantage of using JSON or XML is that your RESTful API becomes platform independent. If you ever expand your API to where other developers wish to consume it, they can do so, regardless of what specific platform or programming language they are using. In other words, the API could be used my PHP, Java, C#, Python, Ruby, or Perl developers.
In other words, any language or platform that can make HTTP requests and can send GET, POST, PUT, DELETE requests can be used to extend or build upon your API. This is the true advantage of REST.
For more information on setting up your controllers to use REST with Spring MVC, see this question. Additionally, check out the Spring MVC Documentation for more information.
Also, if you haven't checked out the Wikipedia article on REST, I strongly encourage you to do so. Finally, another good, classic read on REST is How I Explained REST To My Wife. Enjoy.

Flex 4 - Sending string (such as JSON) using HTTPService

When I use HTTPService.send(paramter) as a POST request, the web server does not appear to see variable "parameter" if it is a string. The server sees the parameter if it's an Object, but I'm looking to use something like httpservice.send(JSON.encode(object)); Is this possible?
Why not use the actual request objects.
in your service define request objects and post them or send them as get if you please.
Sample code here: http://pastebin.com/ft7QW2vg
Then just call .send on the service.
on the server you can simlpy process if with request.form (Asp)
Failing which why not append it to the url with a binding expression. (you would need to encode it since you would be more or less faking a url or a get behaviour).

RESTful URLs: "Impractical" Requests, and Requiring One of Two Request Parameters

I have a RESTful URL that requires either the offset or the prefix request parameter (but not both).
GET /users?offset=0&count=20
GET /users?prefix=J&count=20
What's the best way to enforce this rule? Spring has the #RequestParam annotation with the 'required' property for optional parameters, but I want to enforce an "either-or" rule on these two parameters. I know I could do it in the code, but is there another way to do it?
Also, what's the proper way to handle "impractical" requests? Say I have 100 million users; the following request, although properly RESTful, is not something I want to support:
GET /users <-- Gets all 100 million users, crashes server and browser!
What should I send back?
You can create two methods and choose one of them with #RequestMapping's params attribute:
#RequestMapping(..., params = {"prefix", "!offset"})
public String usersWithPrefix(#RequestParam("prefix") ...) { ... }
#RequestMapping(..., params = {"offset", "!prefix"})
public String usersWithOffset(#RequestParam("offset") ...) { ... }
what's the proper way to handle "impractical" requests?
The lesser-practiced principles of REST include the requirement that resources be "discoverable". If you are asked for a complete list of 800 million users and you don't want to provide it, you might instead consider serving a page that describes in some way how to filter the collection: for example, an XForms document or HTML containing a FORM element with fields for offset/prefix/count, or a URI template with the appropriate parameters
Or you could just send a "413 Entity too large" error - edit: no you can't. Sorry, I misread the description of whath this code is for
If you decide to go down the route of just sending the first page, I think I would send it as an HTTP redirect to /users?offset=0&count=20 so that the client has a better idea they've not got the full collection (and if your response contains a link to access subsequent pages, even better)

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