In my aplications I use Hasura for my graphql server and Apollo for the client. I have a postgres schema with snake_case table and field names, but I want to have camelCases keys in my responses' objects. Any known way to achieve that?
I can see that apollo server offers fieldResolver where it can be done(Convert snake_case to camelCase field names in apollo-server-express), but I found no similar option for Hasura/ApolloClient.
To make a long story short - currently, there is no such a solution for Hasura. The best suggestion I could get was to rename the column names manually, one-by-one via the console => DATA section => Modify tab:
you can expose any column with a different name in the GraphQLAPI without you having to rename the column itself...
you can do that in the hasura console as in the picture below
Any way to achieve that?
Check out GraphQL aliases.
https://graphql.org/learn/queries/#aliases
https://hasura.io/blog/customising-alias-graphql-fields-with-hasura/
Example:
# Query
query {
users {
id
name: full_name
email: email_addr
}
}
# Response
{
"data": {
"users": [
{
"id": "3ea1352a-6654-444d-9357-62816ccbd2b3",
"name": "Praveen",
"email": "email#mydomain.com"
}
]
}
}
Related
I'm very new to GraphQL, and i'm trying to perform some example queries to this graph. In particular i'm trying the User schema.
According to that documentation, the schema is the following:
id: ID!
liquidityPositions: [LiquidityPosition!]
usdSwapped: BigDecimal!
And here is query i tried:
{
user (where: {id: "0x7c9C48b7cBEbBDA3268435F20c81f15A538C566C"}) {
id
liquidityPositions
usdSwapped
}
}
This query fails, i keep getting the following response:
{
"errors": [
{
"locations": [
{
"line": 0,
"column": 0
}
],
"message": "No value provided for required argument: `id`"
}
]
}
How can i provide the id field and where am i supposed to provide it? Thanks in advance!
You've got a couple of problems with that query. First, to get a user by id, remove the "where" and curly braces from your query. Secondly, the liquityPositions field needs a selection of subfields. Like so:
{
user (id: "0x7c9C48b7cBEbBDA3268435F20c81f15A538C566C") {
id
liquidityPositions {
id
}
usdSwapped
}
}
That website you linked to will show you errors with your query so you can interactively learn more about what is supported.
I would also suggest running through the introduction to GraphQL here: https://graphql.org/learn/ to get a handle on how things are done.
I am new to GraphQL and I wonder how I can explore an API without a possible wildcard (*) (https://github.com/graphql/graphql-spec/issues/127).
I am currently setting up a headless Craft CMS with GraphQL and I don't really know how my data is nested.
Event with the REST API I have no chance of just getting all the data, because I have to setup all the endpoints and therefore I have to know all field names as well.
So how could I easily explore my CraftCMS data structure?
Thanks for any hints on this.
Cheers
merc
------ Edit -------
If I use #simonpedro s suggestion:
{
__schema {
types {
name
kind
fields {
name
}
}
}
}
I can see a lot of types (?)/fields (?)...
For example I see:
{
"name": "FlexibleContentTeaser",
"kind": "OBJECT",
"fields": [
{
"name": "id"
},
{
"name": "enabled"
},
{
"name": "teaserTitle"
},
{
"name": "text"
},
{
"name": "teaserLink"
},
{
"name": "teaserLinkConnection"
}
]
But now I would like to know how a teaserLink ist structured.
I somehow found out that the teaserLink (it is a field with the type Entries, where I can link to another page) has the properties url & title.
But how would I set up query to explore the properties available within teaserLink?
I tried all sorts of queries, but I am always confrontend with messages like this:
I would be really glad if somebody could give me another pointer how I can find out which properties I can actually query...
Thank you
As far as I'm concerned currently there is no graphql implementation with that capability. However, if what you want to do is to explore the "data structure", i.e, the schema, you should use schema instrospection, which was thought for that (explore the graphql schema). For example, a simple graphql instrospection query would be like this:
{
__schema {
types {
name
kind
fields {
name
}
}
}
}
References:
- https://graphql.org/learn/introspection/
UPDATE for edit:
What you want to do I think is the following:
Make a query like this
{
__schema {
types {
name
kind
fields {
name
type {
fields {
name
}
}
}
}
}
}
And then find the wished type field to grab more information (the fields) from it. Something like this (I don't know if this works, just an idea):
const typeFlexibleContentTeaser = data.__schema.types.find(t => t === "FlexibleContentTeaser")
const teaserLinkField = typeFlexibleContentTeaser.fields.find(f => f.name === "teaserLink")
const teaserLinkField = teaserLinkField.type.fields;
i.e, you have to transverse recursively through the type field.
I was working for the first time on graphql, and I saw that Instagram hash their queries.
I searched something, but I don't know if it is correct. The hash is like a persistedquery stored in a cache memory?
Or am I wrong?
Example: this is my request payload
{
"operationName":"user",
"variables":{},
"query":"query user {\n users {\n username\n createdAt\n _id\n }\n}\n"
}
this is instagram:
query_hash: 60b755363b5c230111347a7a4e242001
variables: %7B%22only_stories%22%3Atrue%7D
(it is in urlencode mode).
Now, how could I hash my query? I'm using NodeJS as backend and react js as frontend.
I would like to understand how it works x)! Thank you guys!
The persisted query is used to improve GraphQL network performance by reducing the request size.
Instead of sending a full query which could be very long, you send a hash to the GraphQL server which will retrieve the full query from the key-value store using the hash as the key.
The key value store can be memcached, redis, etc
The Apollo Server comes with automated persisted queries out of the box. I recommended gives it a try. They have publish a blog about it. https://blog.apollographql.com/automatic-persisted-queries-and-cdn-caching-with-apollo-server-2-0-bf42b3a313de
If you want to build your own solution, you can use this package to do the hashing yourself https://www.npmjs.com/package/hash.js
query_hash (or query_id) does not hash the variables or the parameters, it hashes the payload.
Lets say your actual path is /graphql and your payload is
{
"user": {
"profile": [
"username",
"user_id",
"profile_picture"
],
"feed": {
"posts": {
"data": [
"image_url"
],
"page_size": "{{variables.max_count}}"
}
}
}
}
Then this graphql payload will be hashed and it becomes d4d88dc1500312af6f937f7b804c68c3. Now instead of doing that on /graphql you do /graphql/query/?query_hash=d4d88dc1500312af6f937f7b804c68c3. This way you hashed the payload, as in you hashed the "keys" that are required from the graphql. So when you pass variables as a param then the payload does not actually change, because the variables are constant as well, and you are changing them on the backend, and not in the payload.
Is there a way to perform a REST call to ServiceNow REST API that returns a single column of a table? I would like to query the server table for only the names of the servers and not have the entire record containing some 50 plus fields returned.
The latest REST Table API (as of Eureka, I think) supports the parameter sysparm_fields, which allows you to specify a comma-delimited list of fields to include in the response:
This URL template:
https://YOURINSTANCENAME.service-now.com/api/now/v1/table/incident?sysparm_fields=number,short_description,caller_id.name
Would give you a result with something like:
{
"result": [
{
"caller_id.name": "",
"short_description": "Unable to get to network file shares",
"number": "INC0000002"
}
]
}
Is it possible to setup alias for field names in elasticsearch? (Just like how index names can be aliased)
For example: i have a document {'firstname': 'John', 'lastname': 'smith'}
I would like to alias 'firstname' to 'fn'...
Just a quick update, Elasticsearch 6.4 came up with feature called Alias Datatype. Check the below mapping and query as sample.
Note that the type of the field is alias in the below mapping for fieldname fn
Sample Mapping:
PUT myindex
{
"mappings": {
"_doc": {
"properties": {
"firstname": {
"type": "text"
},
"fn": {
"type": "alias",
"path": "firstname"
}
}
}
}
}
Sample Query:
GET myindex/_search
{
"query": {
"match" : {
"fn" : "Steve"
}
}
}
The idea is to use the alias for actual field on which inverted index is created. Note that fields with alias datatype aren't meant for write operations and its only meant for querying purpose.
Although you can refer to the link I've mentioned for more details, below are just some of the important points.
Field alias is only meant to be used when your index has a single mapping. Index has to be created post 6.xx version or be created in older version with the setting index.mapping.single_type: true
Can be used in querying, aggregations, sorting, highlighting and suggestion operations
Target field must be actual field on which inverted index is created
Cannot create alias of another alias field
Cannot use alias on multiple fields. Single alias, Single field.
Cannot be used as part of source filtering using _source.
There is no direct field alias functionality. However, you could rename the fields upon indexing using the index_name property in your mappings.
index_name : The name of the field that will be stored in the index.
Defaults to the property/field name.
See here for more information: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-core-types.html
Adding alias fn for existing field firstname
PUT myindex/_mapping
{
"properties": {
"fn": {
"type": "alias",
"path": "firstname"
}
}
}
Should work this way as of Elasticsearch 7.
Probably you can try creating an alias on your index with filter on the desired field. Your filter must be written in such a way that it selects all the entries from your field. Please refer Filtered aliases section in here. But I am interested in knowing your use case. Why you want to create alias on particular field.