I'm trying to get a filtered _changes-API stream on CouchDB 2.1.1 to work, but I run into issues.
I only want to receive documents via the changes feed that contain the field "type" with the value "article".
According to the documentation something like this should work:
function (doc, req) {
if (doc.type && doc.type == 'article') {
return true;
}
return false;
}
I created the function above in a new view called type_article in a _design document called filters using Fauxton. When I click on the view I don't see any results there.
Now I want to retrieve the filtered changes feed from the DB using the filter as a GET-parameter:
localhost:5984/my_database/_changes?filter=filters/type_article
The response of CouchDB is
{"error":"not_found","reason":"missing json key: filters"}
Do you have an idea how I can get the filter-functionality to work?
PS: I also tried using the 'emit()' function instead of returning true and false, this returned the expected results, but when trying to query _changes the same error appeared.
Just a note, you actually can use view as a filter for _changes. In this case a document counted passed if a map function emits at least one record for it.
For example, if a design document (called "ddoc") looks something like this:
{"views":
{"type_article":
{"map":
"function(doc) {
if (doc.type && doc.type == 'article') {
emit(doc.name);
}
}"
}
}
}
Then a query would look like localhost:5984/my_database/_changes?filter=_view&view=ddoc/type_article. Note a missing _design prefix and a keyword _view for an attribute filter. Here is a link on an according documentation section: [link]
The only thing to be aware here is that this filter not actually using built view index and therefore not faster than an ordinary filter function.
I found the problem. When you create a view in the Fauxton using small + sign next to the Design Documents menu entry you can only created views. Views are different than filters.
To create a filter that works with the _changes feed click on 'Create Document' and create a document like this:
{
"_id": "_design/filters",
"filters": {
"type_article": "function (doc, req) {\n if (doc.type && doc.type == \"article\") {\n return true;\n } else { \n return false; \n}\n}"
}
}
This will create a new design document called filters with a function type_article.
Related
I'm attempting to use the GitHub ProjectV2 API to query a GitHub Projects beta project to obtain the title or a given GitHub Project Item.
Unfortunately, I'm not well-versed in GraphQL and struggling to complete the query. What am I missing from the following GraphQL query to get this to work?
query {
node(id: \"PROJECT_NODE_ID\") {
... on ProjectV2 {
items(id:\"PROJECT_ITEM_ID\")
}
}
content{
... on DraftIssue {
title
}
}
}
As written, this returns the following error:
Field must have selections (field 'items' returns ProjectV2ItemConnection but has no selections. Did you mean 'items { ... }'?)"}
You're almost there, but there are two issues here:
items returns a Connection, which means you still need to include another set of curly braces to "select" which fields you'd like.
The GitHub ProjectsV2 API doesn't look like it supports selection of individual items yet, only paginating through a list of items. This means that what you actually want to use is something like:
query {
node(id: \"PROJECT_NODE_ID\") {
... on ProjectV2 {
items(first: 10) {
nodes {
content {
... on DraftIssue {
title
}
}
}
}
}
}
}
This issue is migrated from a question on our Github account because we want the answer to be available to others. Here is the original question:
Hello,
Following is the InstanceQuery I tried
http://localhost:3000/3_0_1/Questionnaire/jamana/$graphql?query={id}
I am receiving back response as Cannot query field \"id\" on type \"Questionnaire_Query\"
So what is the right format I should try ?
https://build.fhir.org/graphql.html has a sample as http://test.fhir.org/r3/Patient/example/$graphql?query={name{text,given,family}}.Its working in their server. I cannot get the response When I try similarly in our graphql-fhir.
Original answer from Github:
We are using named queries since we are using express-graphql. I do not believe that is valid syntax. Also, the url provided does not seem to work, I just get an OperationOutcome saying the patient does not exist, which is not a valid GraphQL response.
Can you try changing your query from:
http://localhost:3000/3_0_1/Questionnaire/jamana/$graphql?query={id}
to this:
http://localhost:3000/3_0_1/Questionnaire/jamana/$graphql?query={Questionnaire{id}}
When writing the query, you need to provide the return type as part of the instance query. You should get a response that looks like similar to this(if you have implemented your resolver you will have data and not null):
{
"data": {
"Questionnaire": {
"id": null
}
}
}
and from a later comment:
If you are getting null then you are doing it correctly, but you haven't wrote a query or connected it to a data source. You still need to return the questionnaire in the resolver.
Where you are seeing this:
instance: {
name: 'Questionnaire',
path: '/3_0_1/Questionnaire/:id',
query: QuestionnaireInstanceQuery,
},
You are seeing the endpoint being registered with an id parameter, which is different from a GraphQL argument. This is just an express argument. If you navigate to the questionnaire/query.js file, you can see that the QuestionnaireInstanceQuery query has a different resolver than the standard QuestionnaireQuery. So in your questionnaire/resolver.js file, if you want both query and instance query to work, you need to implement both resolvers.
e.g.
// This is for the standard query
module.exports.getQuestionnaire = function getQuestionnaire(
root,
args,
context = {},
info,
) {
let { server, version, req, res } = context;
// Do query and return questionnaire
return {};
};
// This one is for a questionnaire instance
module.exports.getQuestionnaireInstance = function getQuestionnaireInstance(
root,
args,
context = {},
info,
) {
let { server, version, req, res } = context;
// req.params.id is your questionnaire id, use that for your query here
// queryQuestionnaireById does not exist, it is pseudo code
// you need to query your database here with the id
let questionnaire = queryQuestionnaireById(req.params.id);
// return the correct questionnaire here, default returns {},
// which is why you see null, because no data is returned
return questionnaire;
};
This works fine
query QryTopics {
topics {
nodes {
name
topicId
count
}
}
}
But I want a filtered result. I'm new to graphql but I see a param on this collection called 'where', after 'first', 'last', 'after' etc... How can I use that? Its type is 'RootTopicsTermArgs' which is likely something autogenerated from my schema. It has fields, one of which is 'childless' of Boolean. What I'm trying to do, is return only topics (a custom taxonomy in Wordpress) which have posts tagged with them. Basically it prevents me from doing this on the client.
data.data.topics.nodes.filter(n => n.count !== null)
Can anyone direct me to a good example of using where args with a collection? I have tried every permutation of syntax I could think of. Inlcuding
topics(where:childless:true)
topics(where: childless: 'true')
topics(where: new RootTopicsTermArgs())
etc...
Obviously those are all wrong.
If a custom taxonomy, such as Topics, is registered to "show_in_graphql" and is part of your Schema you can query using arguments like so:
query Topics {
topics(where: {childless: true}) {
edges {
node {
id
name
}
}
}
}
Additionally, you could use a static query combined with variables, like so:
query Topics($where:RootTopicsTermArgs!) {
topics(where:$where) {
edges {
node {
id
name
}
}
}
}
$variables = {
"where": {
"childless": true
}
};
One thing I would recommend is using a GraphiQL IDE, such as https://github.com/skevy/graphiql-app, which will help with validating your queries by providing hints as you type, and visual indicators of invalid queries.
You can see an example of using arguments to query terms here: https://playground.wpgraphql.com/#/connections-and-arguments
I have a list view that can be sorted, searched and filtered. From that list view the user can edit items in multiple steps. Finally after editing and reviewing the changes the user goes back to the list. Now I want the list to use the same sorting, search term and filters that the user set before and show the correct results.
How can multiple paramters (sorting, search, filter) be stored and reused when showing the list action?
Possible unsatisfactory ways that I thought of:
pass through all the needed parameters. Does work hardly if there are multiple actions involved between the two list action calls
save the parameters in the session object. This seems to require a lot of code to handle multiple parameters (check if parameter was passed to action, store new value, if parameter was not passed, get old parameter from session, handle empty string parameters):
Long longParameter
if(params.containsKey('longParameter')) {
longParameter = params.getLong('longParameter')
session.setAttribute('longParameter', longParameter)
} else {
longParameter = session.getAttribute('longParameter') as Long
params['longParameter'] = longParameter
}
If you want to make it more generic you could use an Interceptor instead.
This could perhaps be generalized like this:
class SessionParamInterceptor {
SessionParamInterceptor() {
matchAll() // You could match only controllers that are relevant.
}
static final List<String> sessionParams = ['myParam','otherParam','coolParam']
boolean before() {
sessionParams.each {
// If the request contains param, then set it in session
if (params.containsKey(it)) {
session[it] = params[it]
} else {
// Else, get the value from session (it will be null, if not present)
params[it] = session[it]
}
}
true
}
}
The static sessionParams holds the parameters you want to store/retrieve from session.
If the params contains an element from the list, it is stored in session under the same name. If not, it is taken from session (given that it exists).
In your controller, you can now just access params.getLong('theParam') like you always would. You could also use Grails parameter conversion:
def myAction(Long theParam) {
}
Lots of LOC saved.
I use the session as well. Here is a sample that you may adapt to your needs:
def list() {
if (request.method == 'GET' && !request.queryString) {
if (session[controllerName]) {
// Recall params from memory
params.putAll(session[controllerName])
}
} else {
// Save params to memory and redirect to get clean URL
session[controllerName] = extractParams(params)
redirect(action: actionName)
return
}
// Do your actions here...
}
def extractParams(params) {
def ret = [:]
params.each { entry ->
if (entry.key.startsWith("filter_") || entry.key == "max" || entry.key == "offset" || entry.key == "sort" || entry.key == "order") {
ret[entry.key] = entry.value
}
}
return ret
}
Using session is your best bet. Just save the preference when preferred. I mean, when user sorts, or filter, just save that information in the session, for that particular <controller>.<action>, before returning the page. Next time, check the session, if it has anything related to that <controller>.<action>, apply those; otherwise render the default page.
You might like to use some Interceptor for this, as suggested by sbglasius, here.
I hope you're getting my point.
I have two documents that looks a bit like so:
Doc
{
_id: AAA,
creator_id: ...,
data: ...
}
DataKey
{
_id: ...,
credits_left: 500,
times_used: 0,
data_id: AAA
}
What I want to do is create a view which would allow me to pass the DataKey id (key=DataKey _id) and get both the information of the DataKey and the Doc.
My attempt:
I first tried embedding the DataKey inside the Doc and used a map function like so:
function (doc)
{
if (doc.type == "Doc")
{
var ids = [];
for (var i in doc.keys)
ids.push(doc.keys[i]._id);
emit(ids, doc);
}
}
But i ran into two problems:
There can be multiple DataKey's per
Doc so using startkey=[idhere...]
and endkey=[idhere..., {}] didn't
work (only worked if the key happend
to be the first one in the array).
All the data keys need to be unique, and I would prefer not making a seperate document like {_id = datakey} to reserve the key.
Does anyone have ideas how I can accomplish this? Let me know if anything is unclear.
-----EDIT-----
I forgot to mention that in my application I do not know what the Doc ID is, so I need to be able to search on the DataKey's ID.
I think what you want is
function (doc)
{
if (doc.type == "Doc")
{
emit([doc._id, 0], doc);
}
if(doc.type == "DataKey")
{
emit([doc.data_id, 1], doc);
}
}
Now, query the view with key=["AAA"] and you will see a list of all docs. The first one will be the real "Doc" document. All the rest will be "DataKey" documents which reference the first doc.
This is a common technique, called CouchDB view collation.