I'm maintaining a site written in GWT (2.5.0) that is used internally by our development team, and I've been experimenting with using AutoBeans for client side json parsing. I have a few objects with json that is not well defined — a developer can dump whatever json string he wants in there — so I'm using a Splittable property. In order to support editing this arbitrary json I'd like to convert a String into a Splittable, but I haven't found a straight-forward way of accomplishing this. Do I need to implement this interface myself or resort to something hacky like wrapping the json in another json object I can then decode into a throw-away AutoBean just to get a Splittable of the original json?
StringQuoter is the utility class which we do much of our manual Splittable work with.
Just user StringQuoter.create("some string"); to produce a Splittable whose payload is
"some string"
Once you have that splittable, you can assign it to a key in another splittable with the following method:
Splittable.assign(Splittable parent, String propertyName);
However, if you are trying to convert some arbitrary string which contains a JSON structure into a splittable, use StringQuoter.split(..) to create it. The resulting splittable can be queried as normal (i.e. what keys exist/don't exist, etc).
Related
I am working in Swift and I have a set of Data that I can encode as a String like this:
<CONTAINER><Creator type="NSNull"/><Category type="NSNull"/><UMID type="NSArray"><CHILD>d1980b265cbd415c90f5d5f04efcb5df</CHILD><CHILD>7e0252c137c249fc92bd0f844effe27f</CHILD></UMID><Channels type="NSNumber">1</Channels></CONTAINER>
I am looking for a way to format this string as XML with indents so I can use XMLParser to properly read through it, which it currently does not. I imagine NSNull is when the object is empty, I just haven't seen this format so I don't know what to search for. Could it be closer to a Dictionary object? If so I'd be happy to format it as that as well.
I've also tried to create a XMLDocument from the data, but it doesn't fix the format.
EDIT:
I wanted to add a bit more information to help clarify what I am trying to do. This string above is derived from an encrypted piece of metadata from a file. In my code I identify the chunk of data that is encrypted, then decrypt it, and then convert that data to a string. It's worth noting that the string ends up having null characters in between each valid character, but I strip those out and end up with this string.
Copying this string into an XML Validator confirms it is valid XML. What is confusing to me is it's format, in which it has Object types such as NSNull and NSNumber. My post was originally hoping to identify this type of format. It seems like more than just XML.
In response to some of the comments, I have used XML Parser delegate with other XML strings and have a basic understanding of how it works. I should have originally mentioned that and instead said that XML Parser does not recognize any of these elements or strings within them.
UPDATE:
The issue ended up being the null characters in between each valid character. Stripping those out and then running it through XML Parser worked great. Thanks all.
When writing a function for AWS Lambda (in Java/Scala), the handler function can have one of different signatures:
// Raw input / output
def handleRequest(is: InputStream): OutputStream = ???
// Using the AWS dependency
def handleRequest(input: APIGatewayProxyRequestEvent, context: Context): APIGatewayProxyResponseEvent = ???
This is the two possible signatures I know of, at least. Maybe there is more.
The difference is that the first one is a raw response, that needs to be packed into a REST response by the API Gateway with manually configured properties like media type and response code.
The second response seems to utilize the Lambda Proxy Integration and will extract all configuration from the APIGatewayProxyResponse.
Now for my question:
The field body of APIGatewayProxyResponse is of type String.
To me it looks like this POJO is serialized to JSON before being sent to the API Gateway.
This would make it impossible to serve binary data like images or PDF files.
The raw OutputStream cannot carry the information about headers etc. (or can it?), which means I cannot serve multiple different media types.
Of course I could convert images, for example, to Base64. But that is far from optimal.
Is there a way I can serve different (binary and non-binary) media types (with correct headers etc.) in a single AWS Lambda handler? How do I have to configure the API Gateway for that?
Note: This answer is based on reading the docs. I haven't tried it in practice so it may not work.
If you open the "Output Format of a Lambda Function for Proxy Integration" section of the documentation you may see isBase64Encoded field and following text:
The output body is marshalled to the frontend as the method response payload. If body is a binary blob, you can encode it as a Base64-encoded string and set isBase64Encoded to true. Otherwise, you can set it to false or leave it unspecified.
And if you open APIGatewayProxyResponse in the .Net library you can see the IsBase64Encoded property there. It looks like it is just Java API that does not expose this field. But all the rest of the infrastructure should support it. You may also see that a similar field was added to APIGatewayProxyRequestEvent.java at some point but not to APIGatewayProxyResponse. So I think a following workaround should work: create your own APIGatewayProxyResponseEvent class with isBase64Encoded field and use it. Or just extend from the standard com.amazonaws.services.lambda.runtime.events.APIGatewayProxyResponseEvent and add this field in your subclass. I expect that if you match the naming convention, it should work. It should be marshalled to a JSON after all.
I'm attempting to parse json from the GitHub API with play-json, and encountering a problem with the merge_commit_sha field on Pull Requests (incidentally, I know this field is deprecated, but don't want to discuss that in this parsing problem!). Unfortunately merge_commit_sha field comes back as the empty string in some cases:
"merge_commit_sha": ""
This is how the field is declared in my case class:
merge_commit_sha: Option[ObjectId],
I have an implicit Format[ObjectId], which does not tolerate the empty string, because that's not a valid value for a Git hash id. I'm also using a play-json macro-generated Read[PullRequest], which I'd like to keep on using, in preference to individually declaring reads for every single field on pull requests.
As I've declared the field to be an Option, I'd like "merge_commit_sha": "" to be read as the value None, but this is not what currently happens - a string is present, so the Format[ObjectId] is invoked, and returns a JsFailure.
One thing I tried was declaring an implicit Format[Option[ObjectId]] with the required behaviour, but it didn't seem to get used by the macro-generated Read[PullRequest].
You can define a custom Reads and Writes yourself.
Using Json.format[MyType] uses a Scala macro. You may be able to hook into that. Although, 'extending' a macro for this one case class just seems wrong.
Custom Reads and Writes might be a little 'boilerplate-like' and boring, but they have their upsides.
For example if your json has a bunch of new fields on it, you wont get a JsError when validating or transforming it to a case class. You only take what you need from the JSON and create objects. It also allows for a separation between your internal model and what you're consuming, which in some cases is preferred.
I hope this helps,
Rhys
EDIT
After using some other JSON libs I may have found what you are looking for.
I know the question was asking specifically after Play JSON.
If you're able to move away from Play JSON, Look at spray-json-shapeless specifically JsNullBehaviour and JsNullNotNone REF.
I'd like to know if it is possible to use the serializer of GWT. When using the rpc-mechnism of GWT, GWT serializes the objects on the client and deserializes the objects on the server. For this mechanism you have to use special servlets (RemoteServiceServlet) of GWT. But i want to use the normal HttpServlets and therefore i have to serialize and deserialize the objects by myself.
All the code you need to look at is in the RemoteServiceServlet.java. Focus on the processCall method.
The RPC.decodeRequest(payload, ...) will give you a RPCRequest object which includes the method to be called and the deserialized parameters.
To encode the response focus on RPC.invokeAndEncodeResponse() and RPC.encodeResponseForSuccess() methods.
[EDITED]
In client-side it's worth to take a look to the proxy classes generated by the RPC generator, concretely the YourService_Proxy.java file. Generated files are left somewhere in your project's folder structure after compiling a project (you can indicate this folder with the -gen though).
The interesting code is in in the RemoteServiceProxy, looking at the createStreamWritter method, you can see how to serialize your objects. In the createStreamReader you can see how to deserialize a message from the server.
See gwt-byte-serializer
SerializerInt ser = new Serializer();
ser.writeValue("test");
ser.writeValue(new int[]{5,1,6});
String buffer = ser.getBuffer();
SerializerInt des = new Serializer(buffer);
des.readString()
des.readIntegerArr()
Is there an easy way to use SerializationStreamWriter for custom purposes without writing an own generator?
(for example html5 storage)
The javadoc of GWT tells very little.
We are writing an implementation for our current project, which does exactly what you want do: serialize an custom object into string and save it into the localstorage, deserialize the string into an object...
So, for me, it is possbile, to use SerializationStreamWriter for serialization, and use SerializationStreamReader for deserialization in CLIENT SIDE.
To realize this,
you don't need a generator for SerializationStreamWriter/SerializationStreamReader, but a generator for TypeSerializer (which implements com.google.gwt.user.client.rpc.impl.SerializerBase). And this is quiet simple, take a look at com.google.gwt.user.rebind.rpc.TypeSerializerCreator, and use it in your generator. OR, if all your custom objects are referenced in one RPC service, you can just use the generated rpc service's TypeSerializer.
And you must write a proper implementation of SerializationStreamWriter OR SerializationStreamReader. Because there has two serialized string formats(request used format and response used format):
IN GWT, you have
ClientSerializationStreamWriter, ClientSerializationStreamReader for client side serialization/deserialization;
ServerSerializationStreamWriter, ServerSerializationStreamReader for server side serialization/deserialization;
Client SerializationStream Writer will serialize the object into FORMAT_1, and only Server SerializationStream Reader can read it (deserialize it into object).
Server SerializationStream Writer will serialize the object into FORMAT_2, and only Client SerializationStream Reader can read it (deserialize it into object).
so what you need to do, if you want to use ClientSerializationStreamWriter to serialize your object, then write a similar implementation of ServerSerializationStreamReader for client side. Or if you want to use ClientSerializationStreamWriter to deserialize the string, then write a similar implementation of ServerSerializationStreamWriter in client side. This is not difficult, because the difference between FORMAT_1 and FORMAT_2 is just the order.
No.
Because the GWT-RPC serialization is asymmetric, it cannot be used for local storage: the server understands what the client sent, the client understands what the server sent, but they won't understand what they themselves wrote.