graphQL using cursor pagination skips one record #4795
Description
Hi, we setup a graphql API using MongoTemplate and we have an issue when using pagination. Basically one record is skipped. Not really sure if it's a Spring Data Mongo or Spring GraphQL or issue on our implementaton.
The controller is setup:
@QueryMapping
public Window<Product> allPaginatedProducts(
@Argument OffsetDateTime lastModified,
ScrollSubrange subrange,
@Argument Optional<Sort> optionalSort
) {
ScrollPosition scrollPosition = subrange.position().orElse(ScrollPosition.offset());
Limit limit = Limit.of(subrange.count().orElse(10));
Sort sort = optionalSort.orElse(Sort.by(Sort.Direction.ASC, "reference", "serialNumber"));
return productRepository.getProducts(new ProductQuery(null, null, lastModified.toInstant(), "XXX"), scrollPosition, limit, sort);
}
The repository code
@Override
public Window<Product> getProducts(ProductQuery productQuery, ScrollPosition scrollPosition, Limit limit, Sort sort) {
Criteria criteria = new Criteria();
...
Query query = query(criteria)
.limit(limit)
.with(sort)
.with(scrollPosition);
return mongoTemplate.query(Product.class)
.matching(query)
.scroll(scrollPosition);
The query
query my {
allPaginatedProducts(first: 3) {
pageInfo {
hasNextPage
hasPreviousPage
startCursor
endCursor
}
edges {
cursor
}
}
}
returns
{
"data": {
"allPaginatedProducts": {
"pageInfo": {
"hasNextPage": true,
"hasPreviousPage": true,
"startCursor": "T18x",
"endCursor": "T18z"
},
"edges": [
{
"cursor": "T18x"
},
{
"cursor": "T18y"
},
{
"cursor": "T18z"
}
]
}
}
}
So now I want to get the first record after the cursor T18x, so I expected to receive T18y but I receive T18z.
query my {
allPaginatedProducts(first: 1, after: "T18x") {
pageInfo {
hasNextPage
hasPreviousPage
startCursor
endCursor
}
edges {
cursor
}
}
}
returns
{
"data": {
"allPaginatedProducts": {
"pageInfo": {
"hasNextPage": true,
"hasPreviousPage": true,
"startCursor": "T18z",
"endCursor": "T18z"
},
"edges": [
{
"cursor": "T18z"
}
]
}
}
}