I will try to make my problem as simple as possible:
I have this serializer:
class DatesSerializer(serializers.Serializer):
date = serializers.CharField(max_length=10)
... bunch of stuff and Others serializers
and on my view.py I have this piece of code:
dates = ["2021-05-02", "2021-06-28", "2021-07-02"]
...
for date in dates:
faults = DatesSerializer({
"date":date,
...
})
return Response({"faults":faults.data, status=200})
I receive a response like these:
{
"faults":{
"date":"2021-07-02"
....
}
}
what I wanted was a response like this one
{
"faults":{
"date":"2021-07-02"
....
},
{
"date":"2021-06-28"
....
}, {
"date":"2021-05-02"
....
}
}
I understand that on my loop I'm overwriting my serializer and that's why I just have the last entry, but I have tried to overcome this by adding on a dict and got nowhere since the key will always be the same, and I'm stuck on how to fix this
What you want is not a valid object. You want a list, and this easily can be accomplished in a loop by appending serializer data on each iteration.
res = []
for date in dates:
serializer = DatesSerializer({
"date":date,
...
})
res.append(serializer.data)
return Response({ "faults": res }, status=200)
Related
I know this is a general question but I have exhausted google and tried many approaches.Any feedback is appreciated.
The HTTPClient is Angular 5+ so it returns an object created from the response JSON data. I get a massive JSON response from an endpoint I have no control over and I want to use about 20% of the response in my app and ignore the rest.
I am really trying hard to avoid using a series of templates or export objects or whatever and trying to force this massive untyped Observable into a typed object with hundreds of fields many being Arrays. All I need for the app is just a Array of very small objects with 3 fields per object. The 3 fields are all over within the JSON response and I want to map them to my object .map only seems to work when you are using the full response object and I can't find an example where .map does custom work besides in the case where you are mapping a few fields to 1 object and I am trying to map to an Array of my small objects.
UPDATED
Basically I want this service to return an object of Type DislayData to the module that subscribes to it but I get just an Object back. This is not what I ultimately need to do but if I can prove I can map the body of the response to my needed return type I can then start to break down the response body and return an Array of the Type I really need based on my silly DisplayData object. Thanks again!
export interface DislayData {
body: any;
}
...
export class DataService {
constructor(private http: HttpClient) { }
/** GET data from the black box */
getData(): Observable<DislayData> {
return this.http.get<HttpResponse<any>>(searchUrl, { observe: 'response' })
.pipe(
map(res => {
return res.body as DislayData;
}
tap(res => console.log(//do stuff with entire respoonse also)),
catchError(err => this.handleError(err)));
}
private handleError(error: HttpErrorResponse) {
...
Do you know the structure of the answering object?
If yes, you can do something like this:
item$ = new BehaviorSubject<any>({});
item = {
foo: 'a',
bar: 'b',
iton: [1, 2, 3],
boo: {
far: 'c'
}
};
logNewItem() {
this.item$
.pipe(
map(response => {
if (response.foo
&& response.iton
&& response.iton.length >= 3
&& response.boo
&& response.boo.far) {
let newItem = {
foo: response.foo,
iton2: response.iton[2],
far: response.boo.far
};
console.log(newItem); // output: Object { foo: "a", iton2: 3, far: "c" }
}
})
)
.subscribe();
this.item$.next(this.item);
}
Basically, you can simply make sure the properties exist, call them directly and map them to a better fitting object.
I heavily recommend creating an interface for the object you're receiving and an interface or class for the object you're mapping to. In that case you can also write the code more compact like this:
[...]
map(response: MyAPIResponse => {
let newItem = new NewItem(response);
console.log(newItem); // output: Object { foo: "a", iton2: 3, far: "c" }
}
})
[...]
class NewItem {
foo: string;
iton2: string;
far: string;
constructor(apiResponse: MyAPIResponse) {
//Validate parameter first
this.foo = apiResponse.foo;
this.iton2 = apiResponse.iton[2];
this.far = apiResponse.boo.far;
and make your code a lot more readable.
I want to serialize incoming_requests and outgoing_requests with a few column values with customized name.
Without serializer, I wrote codes like below.
def index
incoming_requests = FriendRequest.select('id', 'user_id', 'created_at').where(:friend => current_user).order(created_at: :desc)
outgoing_requests = current_user.friend_requests.select('id', 'friend_id', 'created_at')
render json: {
incoming_requests: incoming_requests,
outgoing_requests: outgoing_requests
}
end
However, I want to replace 'select' with serializers. After applying serializers on the output for the codes below, I want to achieve the same result as the result from the above codes.
def index
incoming_requests = FriendRequest.where(:friend => current_user).order(created_at: :desc)
outgoing_requests = current_user.friend_requests
render json: {
incoming_requests: incoming_requests, // want to apply serializer
outgoing_requests: outgoing_requests // want to apply serializer
}
end
So, how can I serialize these incoming and outgoing request objects seperately?
I want to insert data to my table in Cassandra and then return value from column "user_id" instead of full ResultSet. Here it is snippet of my code:
def create(user: User): Future[UUID] = {
insert
.value(_.id, user.id)
.value(_.email, user.email)
.value(_.name, user.name)
.consistencyLevel_=(ConsistencyLevel.ALL)
.future()
.map(r => fromRow(r.one()).id)
}
def fromRow(r: Row): User = {
User(id(r), email(r), name(r))
}
So future() returns Future[ResultSet]. After that I try to retrieve Row from ResultSet, modify it to User and get id eventually. Despite the fact that data were saved to my table I got
ResultSet[ exhausted: true, Columns[]]
columns of the ResultSet are empty and consequently r.one() returned null.
I haven't found any examples for my purpose. So, can phantom-dsl do something like Quill?
val q = quote {
query[Product].insert(lift(Product(0L, "My Product", 1011L))).returning(_.id)
}
So in more recent versions of phantom that create method is automatically generated. More details here. The fromRow method is also automatically generated so you don't need to type it manually.
Long story short, this is what you could use:
def create(user: User): Future[UUID] = {
store(user)
.consistencyLevel_=(ConsistencyLevel.ALL)
.future()
.map(_ => user.id)
}
I am testing RESTful webservice using SoapUI. We use Groovy for that.
I am using jsonslurper to parse the response as Object type.
Our reponse is similar to this:
{
"language":[
{
"result":"PASS",
"name":"ENGLISH",
"fromAndToDate":null
},
{
"result":"FAIL",
"name":"MATHS",
"fromAndToDate": {
"from":"02/09/2016",
"end":"02/09/2016"
}
},
{
"result":"PASS",
"name":"PHYSICS",
"fromAndToDate":null
}
]
}
After this, I stuck up on how to.
Get Array (because this is array (starts with -language)
How to get value from this each array cell by passing the key (I should get the value of result key, if name='MATHS' only.)
I could do it using Java, but as just now learning Groovy I could not understand this. We have different keys with same names.
You can just parse it in to a map, then use standard groovy functions:
def response = '''{
"language":[
{"result":"PASS","name":"ENGLISH","fromAndToDate":null},
{"result":"FAIL","name":"MATHS","fromAndToDate":{"from":"02/09/2016","end":"02/09/2016"}},
{"result":"PASS","name":"PHYSICS","fromAndToDate":null}
]
}'''
import groovy.json.*
// Parse the Json string
def parsed = new JsonSlurper().parseText(response)
// Get the value of "languages" (the list of results)
def listOfCourses = parsed.language
// For this list of results, find the one where name equals 'MATHS'
def maths = listOfCourses.find { it.name == 'MATHS' }
The null safe operator in Groovy is great for reducing code and making things more readable. We can go from this:
def customer = getCustomer(custNo)
if(!customer)
throw new Exception("Invalid customer: ${custNo}")
def policy = customer.getPolicy(policyNo)
if(!policy)
throw new Exception("Invalid policy: ${policyNo}")
def claim = policy.getClaim(claimNo)
if(!claim)
throw new Exception("Invalid claim: ${claimNo}")
..to this...
def claim = getCustomer(custNo)?.getPolicy(policyNo)?.getClaim(claimNo)
But nothing's for free; using null/safe navigation, if claim is null, it's not immediately obvious what caused it: either custNo, policyNo, or claimNo may be invalid.
We could go back and start checking what's null, but that's counterproductive, and actually, it's not even possible since intermediate objects are not stored in variables.
So the question is: Is it possible to identify what was null when chaining method calls using null/safe navigation?
UPDATE
I took another stab at this using dynamic method invocation. It takes an init target (usually a dao) to initialize the object (customer in this case), and a map containing method names as strings (with arguments as values). Using an iterator, invokeChain simply traverses the map (chain); if anything in the chain returns null, identifying the method that caused it becomes trivial.
def invokeChain = { initTarget, chain ->
def obj
chain.eachWithIndex{ it, idx ->
//init obj from dao on first iteration only,
//remaining iterations get from obj itself
obj = (!idx) ? initTarget."$it.key"(it.value) : obj?."$it.key"(it.value)
if(!obj)
throw new Exception("${it.key}(${it.value}) returned null")
}
obj
}
Usage
Mock a customer dao for initTarget...I've inserted null as return type for getClaim(), which should throw an exception.
def static getCustomer = { custNo ->
[ getPolicy: { p ->
[getClaim:{ c ->
null //"Claim #${c}"
}]
}]
}
..using invokeChain, easy as pie:
def claim = invokeChain(this, [getCustomer:123, getPolicy:456, getClaim:789])
...throws exception, as expected:
Exception in thread "main" java.lang.Exception: getClaim(789) returned null
I like this approach because it's compact, readable, and easy to use; what do you think?
I think there is no clear way to do so.
I can be wrong, will check sources later, but safe navigation is a syntax sugar for if statement.
As a hack you can wrap your code with interceptor, trace last method call inside, and then use that info to proide error message.
It will not be cheap, and will cost you some code to realize interception and some performance while running. But you can achieve something like
mayFail("getCusomer", "getPolicy", "getClaim") {
getCustomer(custNo)?.getPolicy(policyNo)?.getClaim(claimNo)
} == "getPolicy" // failed on second step
EDIT: As #tim_yates proved, ?. is a syntax sugar with if construction behind. Thanks Vorg van Geir for the link, I have copied it here, to an answer. He say, it's outdated, and it looks like he is right. I have managed to make ProxyMetaClass work(in Groovy 2.0.6), so given way isn't totally broken. Now I need to specify exact classes to intercept, and I can not find a way to catch inherited method calls.(to simply intercept java.lang.Object)
def logInterceptor = new TracingInterceptor()
logInterceptor.writer = new StringWriter()
def intProxy = ProxyMetaClass.getInstance(Integer)
def stringProxy = ProxyMetaClass.getInstance(String)
intProxy.setInterceptor(logInterceptor)
stringProxy.setInterceptor(logInterceptor)
intProxy.use {
stringProxy.use {
println(("Hello" + "world").size().hashCode())
} }
println(logInterceptor.writer.toString())
All that hell may be wrapped in some utility code, but I highly doubt in necessarity of this. Performance overhead will be awful and some boilerplate code will remain.
The game is not worth the candle.
What about attributions and asserts?
def policy = customer?.policy
def claim = policy?.claim
def number = claim?.number
assert customer, "Invalid customer"
assert policy, 'Invalid policy'
assert claim, 'Invalid claim'
UPDATE:
You already found the solution, but i'd like to contribute with an interceptor idea:
The mock:
def dao = [
getCustomer : { custNo ->
[ getPolicy: { p ->
[getClaim:{ c ->
null //"Claim #${c}"
}]
}]
}
]
The interceptor:
class MethodCallInterceptor {
def delegate
def invokeMethod(String method, args) {
def result = delegate.invokeMethod(method, args)
if (result == null) {
throw new RuntimeException("$method returned null")
}
else {
new MethodCallInterceptor(delegate: result)
}
}
def getProperty(String property ) {
delegate[ property ]
}
void setProperty(String property, value) {
delegate[ property ] = value
}
}
The test:
def interceptedDao = new MethodCallInterceptor(delegate: dao)
try {
interceptedDao.getCustomer(123).getPolicy(456).getClaim(789)
assert false
} catch (e) {
assert e.message.contains( 'getClaim returned null' )
}