add RFC5

Author: tomkralidis

docs/development/rfc/5.md

@@ -0,0 +1,68 @@
+---
+title: RFC5 - Enhanced data limit handling
+---
+
+# RFC5 - Enhanced data limit handling
+
+- date: 2024-11-19
+- author: Tom Kralidis
+- contact: [email protected]
+- status: draft
+- modified: 2024-11-19
+
+## Overview
+
+This RFC describes enhanced limit handling implementation in support of better definition and control on data query limiting.
+
+Currently, pygeoapi defines a `server.limit` configuration directive which corresponds to the `limit` query parameter as part of the OGC API - Features and OGC API - Records `.../items` endpoint.  The following scenarios are missing from this setting:
+
+- the ability for the server to provide a default limit when the user does not explicitly specify a limit
+- the ability for the server to provide a maximum limit when the user specifies a limit that is deemed too large by the server to process
+- given this setting is defined at the server level, it may not be suitable for all datasets in a given configuration
+- limits currently only apply to vector data
+
+## Proposed solution
+
+pygeoapi will define a `limits` configuration parameter that will allow a user to define default and maximum limits for multiple data types.  This parameter will be defined at the server level (`server.limits`) with the ability to override at resource level (`resources[*].limits`).  An example of this setting is shown below:
+
+```yaml
+limits:
+    defaultitems: 10  # applies to vector data
+    maxitems: 500  # applies to vector data
+    maxdistance: [x, y]  # applies to all datasets
+```
+
+The `limits` setting will be applied as follows:
+
+- pygeoapi administrator is able to use at both the `server` and `resources` levels, with `resources` limits overriding server wide `limits` settings
+- no limit specified by client: use `limits.defaultitems` to set the result set size
+- limit specified by client: calculate the minimum of the query parameter and `limits.maxitems` to set the result set size
+- bbox or spatial dimensions: compare distance of request to maximum definition allowed in `limits.maxdistance`
+
+## Implementation
+
+An `evaluate_limit` function will be added to the `pygeoapi` module for use by `pygeoapi.api` accordingly.
+
+### Backwards Compatibility Issues
+
+The `limits` setting fully replaces `server.limit` and represents a compatibility break.  The new functionality will not be backported to other branches.
+
+### Testing
+
+Tests will be added to ensure the expected functionality.
+
+### Documentation
+
+Documentation will be added to the configuration description page.
+
+## Issue and Pull Request tracking
+
+Issue: <https://github.com/geopython/pygeoapi/issues/1856>
+
+Branch: <https://github.com/geopython/pygeoapi/tree/limits>
+
+Pull Request: TBD
+
+## Voting History
+
+TBD

docs/development/rfc/index.md

@@ -14,3 +14,4 @@ the project.
 * [RFC2: Dependency policy](2)
 * [RFC3: Architectural Decision Records](3)
 * [RFC4: GitHub Issue and Pull Request management](4)
+* [RFC5: Enhanced data limit handling](5)