I am trying to use AWS SDK GO v2: https://github.com/aws/aws-sdk-go-v2
And seem to have a hard time unmarshalling the dynamodb.GetItemOutput's Item attribute which is of type map[string]types.AttributeValue.
in AWS SDK GO v1, it's easy to call dynamodbattribute.UnmarshalMap(result.Item, &data) to unmarshal the result. But on v2, I can't find any way to do this.
does anyone have an idea how to do it ?
I was able to find an answer, thanks to Sean McGrail, one of the contributors of the aws-sdk-go-v2 project.
The attributevalue library has methods to unmarshal and marshal the query results to your specific business model/struct:
https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue
I just needed to manually import this library since this wasn't pre-included during download of aws-sdk-go-v2:
go get github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue
Using github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue
You can unmarshal each result item returned by the "Scan" API into a go struct.
var object struct {
PropertyA string `json:"property_a"`
PropertyB string `json:"property_b"`
}
_ = attributevalue.UnmarshalMap(<item>, &object)
Whenever I have to unmarshall JSON data, which is the default output of most AWS SDK responses, I:
Barf out the entire JSON blob (fmt.Println(result))
Copy and paste that into https://mholt.github.io/json-to-go
Snarf the resulting struct into my code, say as MyStruct
Call json.Unmarshal([]byte(result), &MyStruct)
Related
I've just found a simple way to get the some CallLogs (CallerID, Username, To, From, Call duration, Date, Status, ...) from the new Linphone library for swift (SDK 5.0).
I just want to share it with you
Referring to Linphone's documentation, and some testings, I found at least 2 simple ways to retrieve the CallLog and read it:
1. Using CoreDelegateStub
CoreDelegateStub( onCallStateChanged: { (core: Core, call: Call, state: Call.State, message: String) in
So, you can use the call attribute to get the CallerID(Username) for example, like that:
call.callLog?.fromAddress?.username
Remember, the callLog object contains a ton of parameters that you can find in the documentation
2. Using Core from Linphone wrapper
var mCore: Core!
self.mCore.callLogs
In that way, you can retrieve all your call logs in an array, so you will need to choose an item and get the attributes from it like I've shown above.
self.mCore.callLogs[0].fromAddress?.username
When using Kotlin with Moshi to parse an api response, I receive quite a large JSON object back.
However, all of the examples I see, they create an object to pass to the adapter() that includes all of the properties. However, I only need 4-5 of them.
How can I accomplish this? Currently this doesn't work:
val moshi = Moshi.Builder().build()
val jsonAdapter = moshi.adapter(OnLoadUser::class.java)
val onLoadUser = jsonAdapter.nullSafe().lenient().fromJson(data)
It gives this error:
E/EventThread: Task threw exception
java.lang.IllegalArgumentException: Cannot serialize Kotlin type com.biz.app.models.OnLoadUser. Reflective serialization of Kotlin classes without using kotlin-reflect has undefined and unexpected behavior. Please use KotlinJsonAdapterFactory from the moshi-kotlin artifact or use code gen from the moshi-kotlin-codegen artifact.
at com.squareup.moshi.ClassJsonAdapter$1.create(ClassJsonAdapter.java:97)
at com.squareup.moshi.Moshi.adapter(Moshi.java:145)
at com.squareup.moshi.Moshi.adapter(Moshi.java:105)
It's really a large JSON object, and I only need 4 properties:
{
name: 'John Doe',
email: 'john.doe#gmail.com',
token: 'QWERTY',
guid: '1234-5678-ASDF-9012'
...
}
Annotate properties that you want to skip with #Transient, they will be omitted by moshi.
The issue was that I wasn't using the KotlinJsonAdapterFactory(). I had to add it:
val moshi = Moshi.Builder().add(KotlinJsonAdapterFactory()).build()
And also in the gradle.build, so that it was available as an import:
implementation("com.squareup.moshi:moshi-kotlin:1.12.0")
After doing this, it could properly parse the JSON data with a partial Kotlin object.
I need to get Json to my model but i have problems(i am beginner).
my model
https://gist.github.com/anonymous/1c2e88cb83cbeace6f34
and i need to do getting json to my model
and i need json->to model convertion
and i use web service for getting json
and how can i implement object list of jobs to my model
controller
https://gist.github.com/anonymous/c526483b29be0b198bca
i need objects to edit some details and i want to re convert to Json
my opinion is this
i am open new ideas
Thanks...
It looks like you have nearly everything you need there. To convert builds in the JSON to a list of Build, you'd do this:
val js: JsValue = response.json
(js \ "builds").as[List[Build]]
To modify a field, you can do, for example:
val build = builds.head // get the first build
val modifiedBuild = build.copy(name = "new name")
Then to convert that back to being JSON:
Json.toJson(mp)
I was using Breeze v1.1.2 that came with the Hot Towel template which has now been extended to form my project. I made the mistake of updating the NuGet package to the current 1.3.3 (I never learn). Anyway, all was well, and now not so much!
I followed the instructions in the release notes and other docs to change my BreezeWebApiConfig file to:
[assembly: WebActivator.PreApplicationStartMethod(
typeof(BreezeWebApiConfig), "RegisterBreezePreStart")]
namespace MyApp.App_Start {
public static class BreezeWebApiConfig {
public static void RegisterBreezePreStart() {
GlobalConfiguration.Configuration.Routes.MapHttpRoute(
name: "BreezeApi",
routeTemplate: "breeze/{controller}/{action}"
);}}}
And the config.js file (which provides the serviceName to the EntityManager constructor) to:
var remoteServiceName = 'breeze/breeze'; // NEW version
//var remoteServiceName = 'api/breeze'; // OLD version
And my BreezeController if you're interested:
[BreezeController]
public class BreezeController : ApiController
{
readonly EFContextProvider<MyDbContext> _contextProvider =
new EFContextProvider<MyDbContext>();
[HttpGet]
public string Metadata()
{
return _contextProvider.Metadata();
}
[HttpGet]
public IQueryable<SomeItem> SomeItems()
{
// Do stuff here...
}
}
Now I get the "cannot execute _executeQueryCore until metadataStore is populated" error.
What am I missing here?
EDIT:
I perhaps left out the part you needed... Above in the SomeItems() method, the stuff that actually gets done is a call to the GetMeSomeData() method in the MyDBContext class. This method makes the following call to a stored procedure to get the data.
public virtual ObjectResult<SomeItem> GetMeSomeData(string inParam)
{
var p = new object[] { new SqlParameter("#inParam", inParam) };
var retVal = ((IObjectContextAdapter)this).ObjectContext.ExecuteStoreQuery<SomeItem>("exec GetData #SN", p);
return retVal;
}
Now given my limited understanding, the call to Metadata() is not failing, but I don't think it has any idea what the entity model is when coming back, even though somewhere along the line, it should figure that out from the entity model I do have (i.e. SomeItem)? The return string from Metadata() doesn't have any information about the entity. Is there a way to make it aware? Or am I just completely off in left field playing with the daisies?
Hard to say based on this report. Let's see if Breeze is right.
Open the browser debugging tools and look at the network traffic. Do you see an attempt to get metadata from the server before you get that error? If so, did it succeed? Or 404? Or 500? What was the error?
I'm betting it didn't even try. If it didn't, the usual reason is that you tried some Breeze operation before your first query ... and you didn't ask for metadata explicitly either. Did you try to create an entity? That requires metadata.
The point is, you've got to track down the Breeze operation that precipitates the error. Sure everything should just work. The world should be rainbows and unicorns. When it isn't, we heave a sigh, break out the debugger, and start with the information that the error gave us.
And for the rest of you out there ... upgrading to a new Breeze version is a good thing.
Happy coding everyone.
Follow-up to your update
Breeze doesn't know how you get your data on the back-end. If the query result has a recognizable entity in it, Breeze will cache that. It's still up to you in the query callback to ensure that what you deliver to the caller is something meaningful.
You say that you're server-side metadata method doesn't have any idea what SomeItem is? Then it's not much use to the client. If it returns a null string, Breeze may treat that as "no metadata at all" in which case you should be getting the "cannot execute _executeQueryCore until metadataStore is populated" error message. Btw, did you check the network traffic to determine what your server actually returned in response to the metadata request (or if there was such a request)?
There are many ways to create Metadata on the server. The easiest is to use EF ... at least as a modeling tool at design time. What's in that MyDbContext of yours? Why isn't SomeItem in there?
You also can create metadata on the client if you don't want to generate it from the server. You do have to tell the Breeze client that you've made that choice. Much of this is explained in the documentation "Metadata Format".
I get the feeling that you're kind of winging it. You want to stray from the happy path ... and that's cool. But most of us need to learn to walk before we run.
I've been looking on forums for 2 days now and can't find a good answer so I'll just post it.
I appear to be having a problem posting JSON back to the controller to save. The JSON should map to model view but it keeps getting default(constructor)values rather then the values from the POST.
We have a series of JS widgets that contain a data field with json in them. We do all our data manipulation in these widget objects on the client side. When a user wants to save we grab the data we need from the widgets involved and we put it into another JSON object that matches a ViewModel and POST that back to the server.
For example:
$("#Save").click(function () {
if (itemDetails.preparedForSubmit() && itemConnections.preparedForSubmit()) {
itemComposite.data.Details = itemDetails.data;
itemComposite.data.Connections= itemConnections.data;
$.post(MYURL, itemComposite.data);
} else {
alert("failed to save");
}
});
The preparedForSubmit() method simple does stuff like any validation checks or last minute formatting you might need to do client side.
The itemDetails widgets data matches a ViewModel.
The itemConnections widgets data matches a collection of ViewModels.
The Controller looks like this:
[HttpPost]
virtual public JsonResult SaveItemDetailsComposite(ItemComposite inItemData)
{
if (ModelState.IsValid)
{
try
{
_Mapper.Save(itemComposite.Details , itemComposite.Connections);
return Json(true);
}
catch (Exception ex)
{
_log.Error("Exception " + ex.InnerException.Message);
throw;
}
}
return Json(SiteMasterUtilities.CreateValidationErrorResponse(ModelState));
}
The ItemComposite Class is a simple View Model that contains a single itemDetails object and a collection of itemConnections. When it returns data to here it is just getting the default data as if it got a new ItemComposite rather than converting the POST data.
in Firebug I see the data is posted. Although it looks weird not automatically formatted in firebug.
Are you saying that itemComposite.data is formatted as a JSON object? If so, I'm pretty sure you're going to have to de-serialize it before you can cast it to your object. Something like:
ItemComposite ic = jsSerializer.Deserialize<ItemComposite>(this.HttpContext.Request.Params[0]);
You may want to look into a framework like JSON.NET to ensure that your data is being serialized properly when it gets supplied to your Action.
JSON.NET seems like it's one of the main stream frameworks: http://json.codeplex.com/releases/view/43775
Hope this helps.
Cory
You could also use the JSON Serializer in WCF: http://msdn.microsoft.com/en-us/library/system.runtime.serialization.json.datacontractjsonserializer.aspx
SO wouldn't let me put both links in one answer, sorry for the split answer.
Thanks everyone. I think I have solved my problem and I'm pretty sure that I had four issues. For the most part I followed thatSteveguys's suggestion and read more on this article: http://haacked.com/archive/2010/04/15/sending-json-to-an-asp-net-mvc-action-method-argument.aspx
Using jQuery's post() method and specifying json as the type didn't seem to actually send it as json. By using the ajax() method and specifying json it sent it as json.
The JSON.serialize() method was also need to cleanly send over the json.
Also my ViewModel design was a big problem. We are using the MS code analytic build junk and it didn't want me having a setter for my collections in the ViewModel. So me being from a java/hibernate world, thought it didn't need them to bind and it would just come in as a serialized object magically. Once I just suppressed the error and reset up my setters. I am getting the collections now in my controller.
I believe using the MVC2 Future's Value Providers are doing something but it still doesn't convert json dates robustly, So I am still investigating the best way to do that.
I hope my issues help out others.
UPDATE: using this method to update collections of data appears to be super slow. A collection with 200 entries in it and 8 fields per entry takes 3 minutes to get to the controller. Just 1 or 2 entries take very little time. The only thing I know of that is happening between here is data binding to the model view. I don't know if MVC2 provides a easy way to send this much data and bind it.