Pagination args (#255)

* Add initial first/after implementation for pagination args

* Add last/before

* Add tests for before/last

* Working initial implementation for async

* Fix/update tests; working async

* Patch for sync sqlalchemy

not the long term fix

* Minor bind refactor

* Reformat

* Reformat

* Add release.md file

* Reduce number of for loops in mapper; fix some logic errors

* Refactor tests

* Resolve remaining test errors

* Add cases to check for invalid pagination args

* Small fixes + more coverage

* Remove unnecessary list comp

* Fix misplaced setattr

* Reformat

* Address PR feedback from sourcery

* Refactor based on sourcery feedback

* remove unused parent_loader

* run pre-commit

---------

Co-authored-by: Ckk3 <[email protected]>

Author: davidroeca

RELEASE.md

@@ -0,0 +1,167 @@
+Release type: minor
+
+Implement Relay-style cursor pagination for SQLAlchemy relationships by extending the connection resolver and DataLoader to accept pagination arguments, computing pageInfo metadata, and introducing cursor utilities. Add PaginatedLoader to scope DataLoader instances per pagination parameters and update tests to verify pagination behavior.
+
+**New Features**:
+- Support cursor-based pagination (first, after, last, before) on GraphQL relationship fields
+- Introduce PaginatedLoader to manage DataLoader instances per pagination configuration
+
+**Enhancements**:
+- Extend connection resolvers to compute pageInfo fields (hasNextPage, hasPreviousPage, totalCount) and handle forward and backward pagination
+- Add utilities for cursor encoding/decoding and relationship key extraction
+
+**Tests**:
+- Add comprehensive tests for forward and backward pagination scenarios in both synchronous and asynchronous execution contexts
+
+**Examples**:
+
+Get the first three books for a specific author:
+
+```gql
+query {
+  author(id: 1) {
+    id
+    name
+    books(first: 3) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```
+
+Get all books after a specific book's cursor:
+
+```gql
+query($afterBook: String) {
+  author(id: 1) {
+    id
+    name
+    books(after: $afterBook) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```
+
+Get the first three books for a specific author after a specific book's cursor:
+
+```gql
+query($afterBook: String) {
+  author(id: 1) {
+    id
+    name
+    books(first: 3, after: $afterBook) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```
+
+
+Get the last three books for a specific author:
+
+```gql
+query {
+  author(id: 1) {
+    id
+    name
+    books(last: 3) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```
+
+Get all books before a specific book's cursor:
+
+```gql
+query($beforeBook: String) {
+  author(id: 1) {
+    id
+    name
+    books(before: $beforeBook) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```
+
+Get the last three books for a specific author before a specific book's cursor:
+
+```gql
+query($beforeBook: String) {
+  author(id: 1) {
+    id
+    name
+    books(last: 3, before: $beforeBook) {
+      edges {
+        node {
+          id
+          title
+        }
+      }
+      pageInfo {
+        hasNextPage
+        hasPreviousPage
+        startCursor
+        endCursor
+      }
+    }
+  }
+}
+```