René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"bug:sparql.method = \"POST\" silently ignored — SPARQL queries always use GET     ","articleBody":"# Bug Report                                                                                                              \n                                                                                                                              \n    **Describe the bug**                                                                                                      \n    `_query_sparql_endpoint()` in `download.py` attempts to force HTTP POST for SPARQL                                        \n    queries by directly assigning to the attribute:                                                                           \n                                                                                                                              \n    ```python                                                                                                                 \n    sparql.method = \"POST\"                                                                                                    \n                                                                                                                              \n  However,  SPARQLWrapper  does not expose  .method  as a settable public attribute.                                          \n  This assignment is silently ignored and the wrapper defaults to  GET  for all queries.                                      \n                                                                                                                              \n  As a result, large SPARQL queries (e.g. those returned by collection endpoints) are                                         \n  sent as GET requests, causing failures due to URL length limits on the server side.                                         \n                                                                                                                              \n  To Reproduce                                                                                                                \n                                                                                                                              \n  1. Install the client:  pip install databusclient                                                                           \n  2. Download a large collection:                                                                                             \n    databusclient download https://databus.dbpedia.org/dbpedia/collections/dbpedia-snapshot-2022-12                           \n                                                                                                                              \n  3. Observe that the underlying SPARQL query is sent via GET, which may fail for large                                       \n  collection queries that exceed server-side URL length limits.                                                               \n                                                                                                                              \n  Expected behavior                                                                                                           \n  The SPARQL query should be sent via HTTP POST.  SPARQLWrapper  provides the correct                                         \n  API for this:                                                                                                               \n                                                                                                                              \n    sparql.setMethod(\"POST\")   # correct ✅                                                                                   \n    # NOT: sparql.method = \"POST\"  (silently ignored ❌)                                                                      \n                                                                                                                              \n  Root Cause                                                                                                                  \n  File:  databusclient/api/download.py , function  _query_sparql_endpoint() , line 593.                                       \n                                                                                                                              \n    # current (broken)                                                                                                        \n    sparql = SPARQLWrapper(endpoint_url)                                                                                      \n    sparql.method = \"POST\"      # ← has no effect                                                                             \n                                                                                                                              \n    # fix                                                                                                                     \n    sparql = SPARQLWrapper(endpoint_url)                                                                                      \n    sparql.setMethod(\"POST\")    # ← correct SPARQLWrapper API                                                                 \n                                                                                                                              \n  Additional context                                                                                                          \n                                                                                                                              \n  •  SPARQLWrapper  version in use:  ^2.0.0  (see  pyproject.toml )                                                           \n  • The  setMethod  API has been available since SPARQLWrapper 1.x                                                            \n  • This affects any download that goes through a SPARQL query path: collections,                                             \n  custom  --databus  queries, and group/artifact resolution.                                                                  \n                                                                                                                              \n                                                                    ","author":{"url":"https://github.com/Prakhar54-byte","@type":"Person","name":"Prakhar54-byte"},"datePublished":"2026-07-05T20:07:57.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/69/databus-python-client/issues/69"}