feat: upsert with on-conflict support (#142)

* feat: upsert with on-conflict support

* fix: lint

* Update postgrest/base_request_builder.py

Co-authored-by: Anand <40204976+anand2312@users.noreply.github.com>

* chore: docs

* chore: docs

---------

Co-authored-by: Anand <40204976+anand2312@users.noreply.github.com>

Author: Oisangui

postgrest/_async/request_builder.py

@@ -262,6 +262,7 @@ def upsert(
         count: Optional[CountMethod] = None,
         returning: ReturnMethod = ReturnMethod.representation,
         ignore_duplicates: bool = False,
+        on_conflict: str = "",
     ) -> AsyncQueryRequestBuilder:
         """Run an upsert (INSERT ... ON CONFLICT DO UPDATE) query.
 
@@ -270,6 +271,7 @@ def upsert(
             count: The method to use to get the count of rows returned.
             returning: Either 'minimal' or 'representation'
             ignore_duplicates: Whether duplicate rows should be ignored.
+            on_conflict: Specified columns to be made to work with UNIQUE constraint.
         Returns:
             :class:`AsyncQueryRequestBuilder`
         """
@@ -278,6 +280,7 @@ def upsert(
             count=count,
             returning=returning,
             ignore_duplicates=ignore_duplicates,
+            on_conflict=on_conflict
         )
         return AsyncQueryRequestBuilder(
             self.session, self.path, method, headers, params, json

postgrest/_sync/request_builder.py

@@ -262,6 +262,7 @@ def upsert(
         count: Optional[CountMethod] = None,
         returning: ReturnMethod = ReturnMethod.representation,
         ignore_duplicates: bool = False,
+        on_conflict: str = "",
     ) -> SyncQueryRequestBuilder:
         """Run an upsert (INSERT ... ON CONFLICT DO UPDATE) query.
 
@@ -270,6 +271,7 @@ def upsert(
             count: The method to use to get the count of rows returned.
             returning: Either 'minimal' or 'representation'
             ignore_duplicates: Whether duplicate rows should be ignored.
+            on_conflict: Specified columns to be made to work with UNIQUE constraint.
         Returns:
             :class:`SyncQueryRequestBuilder`
         """
@@ -278,6 +280,7 @@ def upsert(
             count=count,
             returning=returning,
             ignore_duplicates=ignore_duplicates,
+            on_conflict=on_conflict
         )
         return SyncQueryRequestBuilder(
             self.session, self.path, method, headers, params, json

postgrest/base_request_builder.py

@@ -70,14 +70,18 @@ def pre_upsert(
     count: Optional[CountMethod],
     returning: ReturnMethod,
     ignore_duplicates: bool,
+    on_conflict: str= "",
 ) -> QueryArgs:
+    query_params = dict()
     prefer_headers = [f"return={returning}"]
     if count:
         prefer_headers.append(f"count={count}")
     resolution = "ignore" if ignore_duplicates else "merge"
     prefer_headers.append(f"resolution={resolution}-duplicates")
     headers = Headers({"Prefer": ",".join(prefer_headers)})
-    return QueryArgs(RequestMethod.POST, QueryParams(), headers, json)
+    if on_conflict:
+        query_params["on_conflict"] = on_conflict
+    return QueryArgs(RequestMethod.POST, QueryParams(query_params), headers, json)
 
 
 def pre_update(