We have implemented our graphql api response like this.
{
data: {...},
skip: 0,
limit: 10,
total: 100,
hasMore: true
}
If I query our api via graphiql the response looks like expected.
But unfortunately the apollo client in our application strips away all properties from the return object except data.
Is this expected behaviour?
And if so, how can I change it or solve this problem differently.
I need to get the total amount of data to implement pagination accordingly.
I know there is a method with fetchMore but it won't tell me the whole amount of entries in the list.
According to the spec only three top-level keys are expected -- data, errors and extensions. If you include additional keys you're going off-spec -- I would not expect any client to attempt to read them.
At the end of the day, this information should be included in your schema and returned as part of the data in the response. Returning it anywhere else (as additional keys in the response, as response headers, etc.) is a bad idea, if for no other reason than the fact that you could have multiple query fields at the root level, in which case you'd only be able to convey pagination information about one of the fields and it'd be unclear which field the information applied to. The same could be said if you have nested fields that can also be paginated.
Related
Say I have a query that returns an array of Customer objects, each one having an id, name, and email, all of which are non-nullable. My resolver loads the data from some source, maybe a database or maybe a downstream system. Most of the data that comes back is fine, but maybe for some reason we're missing the email address for a single customer.
Currently if my resolver just returns the array of all known customers, including the dodgy one, then the entire operation will fail with something like:
{
"data": {
"customers": null
},
"errors": [{
"message": "Cannot return null for non-nullable field Customer.email"
// More error stuff here
}]
}
I get that the validation is supposed to be strict, but now on my UI it fails to load the entire list of customers just because one of them is invalid. It makes it too easy for a single record to poison the entire database.
What I would like is a way to still return the error, but to also have the data field be populated with all of the other, valid Customer records. Is this possible to do with apollo server? Or do I need to manually validate all of the data before trying to return it from my resolver? That would be quite arduous as my real data structure is much more complex.
From this discussion, it seems there's no way to do exactly what I was asking (filter out the invalid records on the server side).
The right approach to this is to either:
Make the email field nullable, so the server can return every Customer, some of which may have incomplete data; or
Make the elements of the top-level Customer array nullable, so the server can return e.g. [customer1, null, customer3]
Option 1 means that the client gets access to more data on an error, so it could still show the rest of the customer's details even if the email is missing. However it makes the data structure less reliable as now anywhere that uses the email might need to do a null check.
Option 2 is a more aggressive failure, nulling out the entire customer because of a single bad field. But it makes it simpler for the client to filter out bad customer records at the top level, allowing the rest of the frontend code to be confident that every customer has an email address.
On that basis I think I prefer option 2.
You might be interested in this article: https://blog.logrocket.com/handling-graphql-errors-like-a-champ-with-unions-and-interfaces/
It talks about using union types to report result status rather than traditional GQL error reporting. Here's an example of how it might look in your case:
type Customer {
id: ID!
name: String!
email: String!
}
interface CustomerErrorInterface {
message: String!
}
type MissingCustomerEmailError implements CustomerErrorInterface {
id: ID!
}
union CustomerResult = Customer | CustomerErrorInterface
type Query {
getCustomers: [CustomerResult!]!
}
Then, on the client side, your query would look something like this:
query getCustomers() {
__typename
... on Customer {
id
name
email
}
... on CustomerErrorInterface {
message
}
... on MissingCustomerEmailError {
id
}
}
This allows you to maintain type safety and avoid nulling things that shouldn't be nullable, while still reporting meaningful results (both successes and error types) that are associated with the data you do have. Using an error interface rather than a concrete error type in the union allows you to leave the option for reporting new types of errors in the future in a backward-compatible way.
The difference between this and the "default" GQL way of error handling (with the top-level errors output) is that reporting the error in an interface allows still giving meaningful reference data (like the id field) in easy locations rather than needing to parse error messages, and different types of errors can provide different reference data as appropriate. Error interface type handling also better fits with regular GraphQL output type patterns (in my opinion) rather than needing to switch on an enum to know how to handle different types of errors.
Allowing null in the output list may accomplish something similar in this particular case, but it makes it impossible to know which piece of data has an error, especially if the data in question does not correspond directly to a user-supplied input that can be found through the path provided by traditional error handling.
Given the following GQL
query getMembers {
repository(owner: "nasa", name: "cumulus") {
mentionableUsers(first: 100) {
nodes {
login
organization(login: "nasa") {
login
}
}
}
}
}
(Query against GitHub v4 GraphQL)
the value for login under organization is either "nasa" or null
I am trying to figure out if it's possible to use #skip against the login/organization so that only contributors to the repo, who are members of the nasa org are shown. I believe for this particular query you can do it another way, but this is just an example.
How would you use #skip/#include with a non boolean. There is minimal documentation on this. While I could filter the response JSON in my client side app, it would be more efficient to receive less data sent over the network and then to parse in my app.
Playing in GraphQLi I received errors trying this various ways - maybe its only possible if the field returns a boolean itself?
e.g., I couldn't do login #skip(if login==null). I also tried setting a value to null in the variables section and the referencing it in the query, but none of the variations I tried work.
What I would really like to do is not include the parent if the child field is some value. e.g., if login=null then don't include that mentionable user. There is no search field option on mentionableUser. From my reading, I am guessing that the only way to do this would be if the API was modified to put a search or filter field on the mentionalbeUsers, otherwise I would need to do this with my client?
Couple of points.
Both the #skip and #include directives provide the same functionality -- allowing the client to arbitrarily chose whether a field should be included in the request.
Let's say we have a query like:
query ($skipBar: Boolean!) {
foo
bar #skip(if: $skipBar)
}
If I set skipBar to true, I am effectively just sending this query:
query {
foo
}
If I set it to false, I am effectively just sending this query:
query {
foo
bar
}
As a client, my logic has to determine the value to assign to skipBar, but I could just as easily use that same logic to decide between sending one of those two queries. In other words, like variables and fragments, #skip and #include are simply a convenient way to keep things DRY on the client-side. They cannot be used to filter the result returned by the server.
GraphQL syntax does not support expressions (or for that matter, any sort of references to parts of the response). Additionally, #skip and #include only take a single argument (if) and that argument must be passed a Boolean -- either as a variable or as a literal value. Even if you could somehow pass an expression to the if argument, though, the directives determine whether the field is included in the request, period. So if the skipped field is part of a returned List (like a List of nodes), it will be absent from every node when it's skipped.
So, is there a workaround?
Not really :( As you've already guessed, if the GitHub API doesn't provide a way to filter a field, there's not much you can do as a client -- you'll have to apply the filtering logic client-side.
I know this has been asked a couple of times before, but I have found no definitive solution to whether this is possible with GraphQL. And I have a strong feeling this should be possible as it should be relatively easy to implement due to GraphQL queries running sequentially in Apollo.
I have a situation where I'm doing a GraphQL mutation first on the client, and then immediately after doing a query which uses the results from the previous query. This causes a needlessly long response time waiting for the server to respond to both requests. The requests look like this:
mutation createWebSession($authId: ID!) {
webSession: createWebSession(authId: $authId) {
token
userId
}
}
query listUserPaymentMethods($userId: ID!) {
userPaymentMethods: paymentMethods(userId: $userId) {
id
}
}
I know that one simple band-aid solution to avoid making 2 round trips to the server is creating a new single GraphQL mutation endpoint that does both services on the back end. But that seems to defeat the purpose of writing modular, reusable GraphQL endpoints. As such, I'm curious if someone knows if Apollo GraphQL supports a cleaner way to chain 2 requests in which the results from the previous one are available to the next one as inputs.
Any help would be greatly appreciated, thanks.
This is a limitation that specific to GraphQL in general. There is no way to do this in a single request for a couple of reasons:
While a GraphQL document may include any number of operations, only a single operation will be executed. If a document includes multiple operations, all operations must be named and the request must include an operationName parameter that specifies which operation to execute. In other words, while you can combine multiple queries into a single operation, or multiple mutations into a single operation, you cannot cannot mix-and-match queries and mutations.
Given any two fields that share the same "parent" field, both fields will resolve at the same time. The only exception to this are root level mutation fields, which do resolve in sequence. As such, GraphQL does not support any syntax that would let you reference another field and use it as the input to some argument.
One possible workaround is to include a field in your createWebSession payload type whose field is the Query type. I illustrate this approach in this article as a means of refetching queries but it would work for what you're trying to do as well.
Is there an easy way to ask the google api ruby client to just give you back the stock HTTP response, rather than to perform the lovely, but slightly limiting translation into one of their ruby representable objects?
e.g.
response = Gmail.client.get_user_message("me", id)
=> #<Google::Apis::GmailV1::Message
response = Gmail.client.list_user_messages("me")
=> #<Google::Apis::GmailV1::ListMessagesResponse
but
response = Gmail.client.delete_user_message("me", id)
=>nil #successfully deleted
Now that's all fine and dandy, except that sometimes I just want to know what sort of response is going to come back. i.e. an HTTP response with maybe some JSON in the body. And then I'll worry about what I do with it...
I can take the response and use the
response.to_json
to get the body of the json that would have come back (though I still won't have the response code, and I need to KNOW that it's one of those objects first).
The client library is definitely getting that, it's just converting it into these objects before it lets me see it. And if I don't know that it's a google object (and not nil) I can't run that to_json consistently....
Any ideas other than second guess what google is going to send me back?
(I should note that this has come about when trying to move a library from dealing with their 0.8 api to their 0.9 api, so call me a cynic if you must but my faith that google won't make breaking changes to those objects returned is at a low ebb...
As far as I know, it is possible to ask the server to send only the fields you really need and get a partial response instead of the default full response as mentioned in Performance Tips.
However, I suggest that you please check the documentation for the specific API you are using to see if the field you're looking for is currently supported. For the Gmail API, you may go through Working with partial resources.
Here are the two types of partial requests that you can use:
Partial response: A request where you specify which fields to include in the response (use the fields request parameter).
Patch: An update request where you send only the fields you want to change (use the PATCH HTTP verb).
Hope that helps!
Why are there GET and POST requests in AJAX as it does not affect page URL anyway? What difference does it make by passing sensitive data over GET in AJAX as the data is not getting reflected to page URL?
You should use the proper HTTP verb according to what you require from your web service.
When dealing with a Collection URI like: http://example.com/resources/
GET: List the members of the collection, complete with their member URIs for further navigation. For example, list all the cars for sale.
PUT: Meaning defined as "replace the entire collection with another collection".
POST: Create a new entry in the collection where the ID is assigned automatically by the collection. The ID created is usually included as part of the data returned by this operation.
DELETE: Meaning defined as "delete the entire collection".
When dealing with a Member URI like: http://example.com/resources/7HOU57Y
GET: Retrieve a representation of the addressed member of the collection expressed in an appropriate MIME type.
PUT: Update the addressed member of the collection or create it with the specified ID.
POST: Treats the addressed member as a collection in its own right and creates a new subordinate of it.
DELETE: Delete the addressed member of the collection.
Source: Wikipedia
Well, as for GET, you still have the url length limitation. Other than that, it is quite conceivable that the server treats POST and GET requests differently; thus the need to be able to specify what request you're doing.
Another difference between GET and POST is the way caching is handled in browsers. POST response is never cached. GET may or may not be cached based on the caching rules specified in your response headers.
Two primary reasons for having them:
GET requests have some pretty restrictive limitations on size; POST are typically capable of containing much more information.
The backend may be expecting GET or POST, depending on how it's designed. We need the flexibility of doing a GET if the backend expects one, or a POST if that's what it's expecting.
It's simply down to respecting the rules of the http protocol.
Get - calls must be idempotent. This means that if you call it multiple times you will get the same result. It is not intended to change the underlying data. You might use this for a search box etc.
Post - calls are NOT idempotent. It is allowed to make a change to the underlying data, so might be used in a create method. If you call it multiple times you will create multiple entries.
You normally send parameters to the AJAX script, it returns data based on these parameters. It works just like a form that has method="get" or method="post". When using the GET method, the parameters are passed in the query string. When using POST method, the parameters are sent in the post body.
Generally, if your parameters have very few characters and do not contain sensitive information then you send them via GET method. Sensitive data (e.g. password) or long text (e.g. an 8000 character long bio of a person) are better sent via POST method.
Thanks..
I mainly use the GET method with Ajax and I haven't got any problems until now except the following:
Internet Explorer (unlike Firefox and Google Chrome) cache GET calling if using the same GET values.
So, using some interval with Ajax GET can show the same results unless you change URL with irrelevant random number usage for each Ajax GET.
Others have covered the main points (context/idempotency, and size), but i'll add another: encryption. If you are using SSL and want to encrypt your input args, you need to use POST.
When we use the GET method in Ajax, only the content of the value of the field is sent, not the format in which the content is. For example, content in the text area is just added in the URL in case of the GET method (without a new line character). That is not the case in the POST method.