Channels
#ktor
Title
# ktor
a
Ayodele
06/30/2020, 10:19 AMHii guys so I'm working on a microservice
I'm using httpclient to plug into the UberApi and I'm getting results in the desired route in the localhost
Now i need to plug it to my ktorservice so I can use a Post request from the Android end and get desired results on mobile client
h
Hamza
06/30/2020, 10:20 AMyou are not asking a specific question
😁 1
a
Ayodele
06/30/2020, 10:22 AMOkay i need help on how i can make the data i got available to the android end.
My idea of how this works is that you need a ktor client to plug into the UberApi which i have done and i need to plug it to my ktor server to make it available
Making it available is what i dont know how to do @Hamza
r
Rémy
06/30/2020, 10:24 AMMake an endpoint :
• call Uber API
• transform data received to your own
• respond to client Android with your data
?
a
Ayodele
06/30/2020, 10:27 AMYeah
I have called the UberApi
Transforming data can be done in what ways please
Its my first time doing backend @Rémy
r
Rémy
06/30/2020, 10:32 AMNo problem, I’m not an expert too (Android developer first 🙂). You made like a middleware, I did that too, between a third api and you client.
I did things in the endpoint method (my previous message).
Do you have small example code to show ?
a
Ayodele
06/30/2020, 10:43 AM Copy code
val client = HttpClient()
val data = <http://client.post|client.post><String>(requestURL) {
header("Authorization", Auth.authKey)
body =
"""{
|"pickup_stop": {"lat": ${start.lat}, "lng": ${start.lng}},
|"destination_stops": [{"lat": ${end.lat}, "lng": ${end.lng}}],
|"payment_method_id": "${paymentMethod}",
|"payment_method_type": "default",
|"timezone": "${timeZone}",
|"preliminary": "true"
|}""".trimMargin()
}
client.close()
return data Copy code
get("/BoltRides") {
call.respondText(getBoltRides(location(51.5073509, -0.1277583), location(51.5073509, -0.1277583)))
}@Rémy
This is how i'm getting for bolt
the route is in application.Kt
r
Rémy
06/30/2020, 10:47 AMDo you have something in return of your getBoltRides first ?
a
Ayodele
06/30/2020, 10:49 AMI can get data in my postman, returns a largeset of data altogether
@Rémy
r
Rémy
06/30/2020, 10:51 AMOk, I think your mapping, or something else is messed up. Are you using the native Ktor client (I ask because I use a different one to consume others APIs, a habit from Android => OkHttp) ?
a
Ayodele
06/30/2020, 10:52 AMyes
Copy code
import io.ktor.client.HttpClient@Rémy
r
Rémy
06/30/2020, 10:53 AMOkay I’m looking documentation.
a
arjun
06/30/2020, 10:53 AM Copy code
<http://httpClient.post|httpClient.post><ClassName>r
Rémy
06/30/2020, 10:56 AMIt was my first expectation, but did you log you api call to handle error first ?
Maybe, your authentication isn’t well implemented.
And yes, a (data) class as dto is a better practice.
a
Ayodele
06/30/2020, 10:57 AM@arjun will that help me if i change it to a data class?
r
Rémy
06/30/2020, 10:58 AMYou need the call logs first. To debug properly your problem.
a
Ayodele
06/30/2020, 10:59 AMokay, first time hearing about that. you mean log like android?
a
arjun
06/30/2020, 11:00 AM1. Cast the response to DTO,
2. have a try catch to see if u are getting any exception
3. better to create a request DTO and assign the instance to body rather than having a JSON there.
4. Set content-type header if its not picking JSON by default
r
Rémy
06/30/2020, 11:03 AMSomehing might help you too : https://ktor.io/clients/http-client/features/logging.html
a
Ayodele
06/30/2020, 11:05 AMokay thanks
does that mean I dont really need a repository pattern or Interface? @arjun @Rémy
r
Rémy
06/30/2020, 11:07 AMIt means you have to found the root cause first 🙂 dto instead of a String is a good practice. But, to debug properly, you need the error log 😉 Step by step 😄
Let me now if you found the error.
a
Ayodele
06/30/2020, 11:09 AMmmm, i'm not getting any errors
i'm getting my desired results
are you saying there might be potential errors
?
@Rémy
r
Rémy
06/30/2020, 11:11 AMAlright you received yours data isn’t it ?
a
Ayodele
06/30/2020, 11:12 AMyes
r
Rémy
06/30/2020, 11:13 AMSo, what’s the problem ? Your client doesn’t get the response ?
a
Ayodele
06/30/2020, 11:14 AMor I guess i'm not mean to use GET in the application.kt?
i only used that to see if i could get the result
the data is a verylarge one and I dont need most of the info its sending, is there a way i can streamline it so I can get it in my client?
r
Rémy
06/30/2020, 11:26 AMIf you want just some informations, you have to make a data mapping on a smaller object who fit your needs.
An interface / class / data class map the API response, then, you can make an other object with just some properties. Then, you send it to your client.
a
arjun
06/30/2020, 11:28 AM@Ayodele how are u getting the data now? what solved the problem ?
➕ 1
r
Rémy
06/30/2020, 11:28 AMMake the mapping on the backend side. Client doesn’t need too much infos.
As I understand, problem wasn’t retrieving api informations but informations mapping, isn’t it @Ayodele?
a
Ayodele
06/30/2020, 11:31 AM@arjun @Rémy
i've been getting the data
what is confusing me is how to expose this to the client because this backend service will be hosted
what i want basically is to be able to call myapp.herokuapp.com/boltride through a POST request from an adnroid app and get my data the way I'm getting it now
@arjun
with less data of course
r
Rémy
06/30/2020, 11:35 AMLike @arjun said, your data response needs to be a class (data), then use it’s properties / data to make your own object to send to Android client.
Copy code
val data = <http://client.post|client.post><UberDataDto>(requestURL) { //...a
Ayodele
06/30/2020, 11:42 AMwhew, Okay thanks
would have been nice if someone had a public repo or something
r
Rémy
06/30/2020, 11:53 AMI think but I don’t have link. Do you have the Uber endpoint definition, to be able to create the DTO ?
a
Ayodele
06/30/2020, 11:59 AMi'm sorry
definition?
@Rémy
r
Rémy
06/30/2020, 12:01 PMEach endpoint has a response definitions, normally it’s in the Uber API document. Like /getUberDriver => 200 : { “id”: string, “name”: string, age: number, ... }
a
arjun
06/30/2020, 12:04 PM Copy code
fun getRides(request: PickupRequest): PickupResponse {
return try {
val response = <http://httpClient.post|httpClient.post><PickupResponse> {
header("Content-Type", ContentType.Application.Json.toString())
url(requestUrl)
body = request
}
response
} catch(e: Exception) {
logger.error(e.message, e)
null
}
}👏 1
a
Ayodele
06/30/2020, 12:12 PMhmm, this would help
thanks @Rémy @arjun
🙂 1
hi @Rémy @arjun
will this work
Copy code
data class BoltResponse (
val message : String,
val city : String,
val searchCategories : List<Rides>
):Serializablemessage. city and searchCategories is what i'm getting
searchCategories is a list
r
Rémy
06/30/2020, 1:30 PMI don’t know what the service send. I suppose it’s alright 🙂
a
Ayodele
06/30/2020, 1:32 PMYeah
🙂 1
hi @Rémy @arjun
I'm getting this error
ERROR Application - Unhandled: GET - /BoltRidesjava.lang.IllegalStateException: Request cannot be executed; I/O reactor status: STOPPEDI used a logger
Copy code
get("/BoltRides") {
call.respond(getBoltRides(location(51.5073509, -0.1277583), location(51.5073509, -0.1277583)))
}this is how i'm calling it after I started using a DTO i coukdnt use respond text any longer
r
Rémy
07/01/2020, 6:51 AMIf you extract the method from the response and put result data in an object. What’s do you reveived ? What’s the return data type ?
You have to serialized you object 🙂
a
Ayodele
07/01/2020, 6:51 AMhow do I do that
my function has a return type of the DTO class
r
Rémy
07/01/2020, 6:52 AMWith Gson, or Jackson ?
a
Ayodele
07/01/2020, 6:52 AMjust like arjun wrote yesterday
Gson
r
Rémy
07/01/2020, 6:54 AMHum, normally Ktor can handle serialization on the fly, but I need to look the documentation.
You have to configure Gson for server side response. And if respond with a Class, Ktor automatically serialized it to Json.
a
Ayodele
07/01/2020, 6:59 AMI
Copy code
install(ContentNegotiation) {
gson {
}
}I have that in my App.kt
r
Rémy
07/01/2020, 6:59 AMYeap, and it didn’t work ?
a
Ayodele
07/01/2020, 7:02 AMnah
must I call client.close() after finishing request?
r
Rémy
07/01/2020, 7:03 AMTry to remove this.
Is it mentioned in the documentation ?
a
Ayodele
07/01/2020, 7:04 AMif i remove it
thers's another error
ERROR Application - Unhandled: GET - /BoltRidesio.ktor.client.call.NoTransformationFoundException: No transformation found: class <http://kotlinx.coroutines.io|kotlinx.coroutines.io>.ByteBufferChannelr
Rémy
07/01/2020, 7:06 AM@Ayodele I will make a small example of what you want to do into a small github repo 🙂 The basics of consume a third api and deserialized / Serialized data to use.
a
Ayodele
07/01/2020, 7:10 AMThanks, that will be really appreciated
Thanks a lot
r
Rémy
07/01/2020, 7:12 AM🙂
Just give me ~ 30 min
a
Ayodele
07/01/2020, 7:17 AMAlright
r
Rémy
07/01/2020, 8:00 AMOkay I push it to Github.
a
Ayodele
07/01/2020, 8:01 AMurl?
r
Rémy
07/01/2020, 8:04 AM2 secs
Really simple case.
a
Ayodele
07/01/2020, 8:09 AMThanks alot
hey I figured how to deserialize it
Thanks
its working now
👏 1
r
Rémy
07/01/2020, 8:28 AMYou understood the concept, and it’s the main goal 🙂
👍 1
In my exampel I forget to close de client 😉
If you execute the call inside a lambda, it’s handle by default.
a
Ayodele
07/01/2020, 1:19 PMyeah, I did that
@Rémy please if i wanna write unit test for a function like this
Copy code
fun getRides(request: PickupRequest): PickupResponse {
return try {
val response = <http://httpClient.post|httpClient.post><PickupResponse> {
header("Content-Type", ContentType.Application.Json.toString())
url(requestUrl)
body = request
}
response
} catch(e: Exception) {
logger.error(e.message, e)
null
}
}how do I go about it?
I have never written unitTests
r
Rémy
07/01/2020, 1:23 PMa
Ayodele
07/01/2020, 1:25 PMmore like when a create a repository?
r
Rémy
07/01/2020, 1:35 PMTest how you manage your data inside your application, and what you send to the client.
a
Ayodele
07/01/2020, 1:36 PMAlright
Thanks
😉 1
a
arjun
07/01/2020, 2:31 PMfor DB it makes sense to write integration tests. for a client, u just need to mock the response and test any custom logic (like u wanted to create a custom DTO from a big object)
👍 1
a
Ayodele
07/03/2020, 9:30 AMHi @Rémy please how to I log in ktor
like in android LOG.d()
r
Rémy
07/03/2020, 9:32 AMAt this time I never used it, but I place often some println(). You can look at this. Maybe, @arjun had better option / opinion ?
a
Ayodele
07/03/2020, 10:17 AMAlright
a
arjun
07/03/2020, 10:17 AM Copy code
install(CallLogging) {
level = <http://Level.INFO|Level.INFO>
}👍 1
a
Ayodele
07/03/2020, 10:18 AMThanks @arjun
a
arjun
07/03/2020, 10:18 AMand for ur custom logs, https://github.com/MicroUtils/kotlin-logging
a
Ayodele
07/03/2020, 12:27 PM@arjun @Rémy dplease help i'm getting this error
java.io.IOException: Broken delimiter occurred
Hi guys, please i just noticed that my server doesnt receive json requests from android client it only accepts form parameters
r
Rémy
07/03/2020, 2:09 PMWhat’s your endpoint ?
a
Ayodele
07/03/2020, 2:11 PMcould this be this issue?
Copy code
val signUpParameters = call.receive<parameters>()what do people use normally?
call.receive<DTO>()r
Rémy
07/03/2020, 2:20 PMI think you want to receive an object. Not a form.
a
Ayodele
07/03/2020, 2:24 PMyeah
Thanks
r
Rémy
07/03/2020, 2:27 PM😉
a
Ayodele
07/06/2020, 1:36 PMhi @Rémy
please I have a list, bascially an array from an external Api and I want to map the properties i to my own properties in another list so it returns something like List<MyDTO>
please help
r
Rémy
07/06/2020, 1:49 PMCreate a function to map your dto list to your own data.
a
Ayodele
07/06/2020, 1:55 PMdid that it was showing empty array in my response and I'm receiving response from the external Api
Copy code
override suspend fun getResponse(start: Location, end: Location): List<MyDTOResponse>? {
val myResponse = listOf< MyDTOResponse>()
val apiRes = getApiRes(start, end)!!.data.rideCategories
}i did somthing like this
and I tried to equate the properties of myResponse to my apiRes
MyDTOResponse returrned an empty array
r
Rémy
07/06/2020, 1:59 PMI don’t understand correctly your flow. You retrieve some data from API (a list), and you want to make a new list with it ?
a
Ayodele
07/06/2020, 1:59 PMyeah, exactly
r
Rémy
07/06/2020, 2:03 PMJust after you retrieve your api list, then map it to your own objects.
apiRes.forEach { category -> newList.add(MyObject.fromDto(category)) } ? Something like that ?
a
Ayodele
07/06/2020, 2:09 PMwhats MyObject.fromDTO?
r
Rémy
07/06/2020, 2:30 PMYour object which you want to use 🤷♂️
It’s not working ?
a
Ayodele
07/06/2020, 2:36 PMi cant call MyObject, its also a list
do i have to loop?
I know forEach is a loop
got it
i used yourmethod
thanks
r
Rémy
07/06/2020, 5:38 PM😉
a
Ayodele
07/07/2020, 10:15 AMHi @arjun @Rémy Please have you used Jwt before?
I'm trying to use postman for my requests and i noticed postman added a previous;y gotten response, and added it as the Bearer so it was giving me this error
Error: Invalid character in header content ["Authorization"]
do you know what the issue might be?
r
Rémy
07/07/2020, 10:17 AMNo idea 😕
a
arjun
07/07/2020, 10:32 AMcan u be more specific ? for authorization u need a Bearer token. usual format is
Bearer JwtTokena
Ayodele
07/07/2020, 10:33 AMyes
a
arjun
07/07/2020, 10:33 AMdo u need authorization or not ?
a
Ayodele
07/07/2020, 10:33 AMmine looks like this
I need authorization
a
arjun
07/07/2020, 10:42 AMdo you know what is Authorization ? and what you are trying to achieve ?
and do you know what is JWT ?
➕ 1