‘Double Encoding’ issue with Fiori Urls in case of Apache-based Reverse Proxy
The typical infra architecture of an on premisse Fiori deployment includes a reverse proxy that enables access to the Fiori Apps from the internet. A responsibility of the reverse proxy is to forward the received external uri address to the protected internal Fiori resource. The generic pattern here is that the domain part of the external url is mapped to the internal url, and the remainder of the external url is concattenated to the internal url. Some / most reverse proxy products handle encoded special characters in the remainder part, well special, by decoding them before forwarding. However, (a.o.) for Fiori URLs this behaviour is undesired. The encoded characters must be forwarded as is, so that the web dispatcher on Gateway FES can decode them and process the correct decoded uri.
Clarification of the effect due 'double encoding' of Fiori URL:
- Browser requests "https://<external-DNS>/sap/opu/odata/UI2/PAGE_BUILDER_PERS/PageSets('%2FUI2%2FFiori2LaunchpadHome')?$expand=Pages/PageChipInstances/Chip/ChipBags/ChipProperties,Pages/PageChipInstances/RemoteCatalog,Pages/PageChipInstances/ChipInstanceBags/ChipInstanceProperties,AssignedPages,DefaultPage&sap-cache-id=...";
- SAP Gateway FES returns http error 404;
- Error logged on the SAP NetWeaver node is that "http://<SAP web dispatcher / Gateway FES>:8000/sap/opu/odata/UI2/PAGE_BUILDER_PERS/PageSets('%252FUI2%252FFiori2LaunchpadHome')?$expand=Pages/PageChipInstances/Chip/ChipBags/ChipProperties,Pages/PageChipInstances/RemoteCatalog,Pages/PageChipInstances/ChipInstanceBags/ChipInstanceProperties,AssignedPages,DefaultPage&sap-cache-id=..." is an invalid URI
Relevant resources:
- Fiori Launchpad Error via Apache: Failure - Unable to load groups
- Need to allow encoded slashes on Apache
- How to Preserve Encoded character in URL from NAM AG to webserver
- Apache still double encoding slashes after correct config
- 404 page as a result of double-encoded slashes in the URL when using Apache
