When submitting a transaction via 'composer-rest-server' I encapsulate the input parameters in form of JSON-body inside requests. However, I always receive the same JSON-String inside the Body-Response. Is there a way to return some response string from transaction written with JS that will be propagated to the caller inside Response-Body? How is the reverse communication to the caller foreseen in the composer? -- Thx.
This is not currently possible with Hyperledger v0.6 -- there's no way to synchronously propagate return value to the submitter of a transaction.
Related
How does one handle the resource_exists callback in cowboy? After all, to find out whether resource exists - I must query (e.g. database) for resource. But then during the AcceptResource callback (e.g. to_html) I must query for the resource again. Is there any way to prevent this double querying?
Is there any way to preserve that resource for the AcceptResource callback, so that I don't have to pull it form database again?
Reading the cowboy docs, there is flowchart of how a rest request is handled.
In it, the callback resource_exists is called first.
In resource_exists you can add the result of the database query to the State variable that resource_exists returns.
The state is passed as input to the AcceptResource callback where you can use the cached value.
I have an API code, which loads a data necessary for my application.
It's as simple as:
- (void) getDataForKey:(NSString*) key onSuccess:(id (^)())completionBlock
I cache data returned from server, so next calls of that functions should not do network request, until there is some data missing for given key, then I need to load it again from server side.
Everything was okey as long as I had one request per screen, but right now I have a case where I need to do that for every cell on one screen.
Problem is my caching doesn't work because before the response comes in from the first one, 5-6 more are created at the same time.
What could be a solution here to not create multiple network request and make other calls waiting for the first one ?
You can try to make a RequestManager class. Use dictionary to cache the requesting request.
If the next request is the same type as first one, don't make a new request but return the first one. If you choose this solution, you need to manager a completionBlock list then you will be able to send result to all requesters.
If the next request is the same type as first one, waiting in another thread until the first one done. Then make a new request, you API will read cache automatically. Your must make sure your codes are thread-safe.
Or you can use operation queues to do this. Some documents:
Apple: Operation Queues
Soheil Azarpour: How To Use NSOperations and NSOperationQueues
May be there will be so many time consuming solutions for this. I have a trick. Create a BOOL in AppDelegate, its default is FALSE. When you receive first response, then set it TRUE. So when you go to other screen and before making request just check value of your BOOL variable in if condition. If its TRUE means response received so go for it otherwise in else don't do anything.
In a project I am working on, I am calling an https API with a POST request which gives me results as a JSON. I am doing the call with AlamoFire, and parsing this with SwiftJSON.
All goes according to plans, and the JSON is received and can be parsed. But now I want to use the values from the received JSON, and immediately do another call to the same API with a different path and use those values as parameters in the call.
At the moment I am posting a NSNotification and when that NSNotification is received I do the POST call to the other path for the details of the data. This works, but not very consistently.
I think that sometimes the data gets in the wrong sequence and the parameters might not be correct. About 80% of the time it works as expected.
Is this the way to work? Or is this not correct to do it with NSNotification? Any insights on this might help!
If you're using this notification pattern correctly, it should work 100% of the time, not 80% of the time. Or, more accurately, if the network connection or server response fails for reasons outside of your control, you should handle it gracefully. If you need help on that problem, update your question with MCVE and we'll see if we can help you.
In terms of a more efficient way to handle this overall process, the typical pattern would be to initiate the second request from inside the response closure of the first request.
Alamofire.request(.POST, url1, parameters: parameters1).response { request, response, data, error in
// create url2 and/or parameters2
Alamofire.request(.POST, url2, parameters: parameters2).response { request, response, data, error in
// do something with second request
}
}
One would generally only use the notification pattern if there is no reliable relationship between the two processes (e.g. when the first request was initiated, it has no reasonable way of possibly knowing which (if any) secondary request(s) will need to react in response to the first request.
I am currently creating an MVC application that is currently getting a value from a post from a webhook. I think that the problem is that the application is getting the value from the POST verb but then it is not displaying it because the Get verb is being used to display the View so both Verbs are counter acting each other.
The webhook will fire A Json payload to my application successfully because I have code in it that will send the Json payload in a variable via email to my email account.
Dim body = issue.issue.key
mail.Body = body
That is in a try catch block because in order for it to have a value it must have a value in it and the application will perform the GET first, so there is a null value in the body variable, then it does the POST to get the value but it will not display the value, refreshing will just perform the GET preventing it from being displayed. How can I perform both actions at the same time so I can display a value in a ViewBag for example.
ViewBag.response = status + key
This is the type of structure that I would like to implement to try and fix the error but I do not know how to complete all of the steps:
This is what I have got so far:
The POST is coming in from a webhook and I am reading it like this.
Dim reader As System.IO.StreamReader = New System.IO.StreamReader(HttpContext.Request.InputStream)
Dim rawSendGridJSON As String = reader.ReadToEnd()
Dim tempVar As Rootobject = JsonConvert.DeserializeObject(Of Rootobject)(rawSendGridJSON)
System.Diagnostics.Trace.TraceError(rawSendGridJSON)
I am then trying to store the post values in a table like this:
Public Function CallBack(tempTable as temporaryTable)
Dim tempVar As Rootobject = JsonConvert.DeserializeObject(Of Rootobject)(rawSendGridJSON)
tempVar = temporaryTable.tempVar
I then save the new items in the actual table in the database, then I try to display it in a view on another page. This is not working correctly and the problem lies with this line, as the post is not being correctly read in at the right time. (The value is processing correctly as I can use an email method to send the variables in an email back to the application but this application needs to be real-time efficient code).
Is there a better way to use this method and how can I invoke this process that I want to do properly so that I can display the correct information?
Update
To clarify, there are two posts that are happening, the first one is when the user enters in information and submits it. This is then stored in a database and send to JIRA via email. Once JIRA receives the information, it is sends a HTTP POST webhook JSON Payload back to my application with updated information. I then have deserialized the JSON Payload into a variable called issueKey.
The problem is that on the View page that the information is sent to will automatically display a null value first before the value is sent to it, I want the application to work so that it will actually display/store in a database the values from the Webhook JSON Payload but I cannot figure out how to display the values.
I have now set up a communication channel from SignalR to my MVC application, at the moment it is being received by the MVC and I have set up a SignalR chat Hub in my MVC application, but I don't know how to integrate them, how can this be done?
As I understand it, there are two flows at work here. The user posts data, which triggers an email to Jira. Then sometime later (usually quite fast, but not always) JIRA triggers a webhook in the web application with some updated information, and you want to display this updated information to the user somehow, or at least inform the user when the updated information comes back from JIRA.
I would implement a standard Post-Redirect-Get for the user initiated part (as per br4d's comment). I.e. a post to store the data in the database and send email to jira, which returns a redirect to a get which shows the data stored in the database.
Now for the other part I would use signalr to set up some sort of communications channel to the user. The webook could then send a signal (of sorts) through the communication channel to the users browser and either display the data, or trigger a refresh of the page (if you are updating the database with data from Jira).
It is unclear if you are doing straigt mvc, or some sort of SPA application, but it is not really important. The users browser has no way of knowing about the webhook (which is a part of the webapplication and unrelated to the users session), and you need some sort of communication between the webapplication and the browser, and for this signalr is very very good.
According to the document on command objects and data binding. Once you read the params object, that object can never be reused again.
From the documentation:
Binding The Request Body To Command Objects
http://grails.org/doc/2.3.x/guide/theWebLayer.html#commandObjects
Note that the body of the request is being parsed to make that work. Any attempt to read the body of the request after that will fail since the corresponding input stream will be empty. The controller action can either use a command object or it can parse the body of the request on its own (either directly, or by referring to something like request.JSON), but cannot do both.
I'm trying to view the parameters within a filter (which is hit before the controller is requested). Would logging the parameters to a log cause the controller to get a null param object? From the documentation that looks to be the case. However, how can I get access to the params without wiping them out in the filter?
Once you read the params object, that object can never be reused
again.
That is not correct. You can read request parameters over and over again. What cannot be read over and over again is the body of the request. The body and the request parameters are 2 different things.