From 55e43bf6c83892ff7d4dad4c3c8c03e5ad2fa797 Mon Sep 17 00:00:00 2001
From: steve-chavez <stevechavezast@gmail.com>
Date: Fri, 29 Sep 2023 17:55:56 -0300
Subject: [PATCH] fix: incorrect parsing 4 fallback_application_name

---
 CHANGELOG.md            |  1 +
 nix/README.md           | 10 +++++++++-
 src/PostgREST/Config.hs | 31 +++++++++++++++++++++----------
 3 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c5e0585599..91d149cb78 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #2846, Fix error when requesting `Prefer: count=<type>` and doing null filtering on embedded resources - @laurenceisla
  - #2959, Fix setting `default_transaction_isolation` unnecessarily - @steve-chavez
  - #2929, Fix arrow filtering on RPC returning dynamic TABLE with composite type - @steve-chavez
+ - #2970, Fix incorrect URI parsing for adding `fallback_application_name` - @steve-chavez
 
 ## [11.2.0] - 2023-08-10
 
diff --git a/nix/README.md b/nix/README.md
index 33fae433d2..7d5bcbd955 100644
--- a/nix/README.md
+++ b/nix/README.md
@@ -13,7 +13,6 @@ To build PostgREST from your local checkout of the repository, run:
 
 ```bash
 $ nix-build --attr postgrestPackage
-
 ```
 
 This will create a `result` directory that contains the PostgREST binary at
@@ -22,6 +21,15 @@ build the `postgrestPackage` attribute from the Nix expression it finds in our
 `default.nix` (see below for details). Nix will take care of getting the right
 GHC version and all the build dependencies.
 
+You can also build a statically linked binary with:
+
+```bash
+$ nix-build --attr postgrestStatic
+
+$ ldd result/bin/postgrest
+$       not a dynamic executable
+```
+
 ## Binary cache
 
 We recommend that you use the PostgREST binary cache on
diff --git a/src/PostgREST/Config.hs b/src/PostgREST/Config.hs
index 47f4e99abe..2520b1af71 100644
--- a/src/PostgREST/Config.hs
+++ b/src/PostgREST/Config.hs
@@ -49,8 +49,7 @@ import Data.List.NonEmpty      (fromList, toList)
 import Data.Maybe              (fromJust)
 import Data.Scientific         (floatingOrInteger)
 import Network.URI             (escapeURIString,
-                                isUnescapedInURIComponent, parseURI,
-                                uriQuery)
+                                isUnescapedInURIComponent)
 import Numeric                 (readOct, showOct)
 import System.Environment      (getEnvironment)
 import System.Posix.Types      (FileMode)
@@ -472,6 +471,8 @@ readPGRSTEnvironment =
   M.map T.pack . M.fromList . filter (isPrefixOf "PGRST_" . fst) <$> getEnvironment
 
 -- | Adds a `fallback_application_name` value to the connection string. This allows querying the PostgREST version on pg_stat_activity.
+-- | This follows the same logic as libpq for parsing the URI https://github.com/postgres/postgres/blob/a829b704015104f49a11ea007957ef03a03dc0d4/src/interfaces/libpq/fe-connect.c#L5880-L5921
+-- | If there's a postgres URI scheme designator prefix ("postgres://") then the connstring is considered an URI, if not, it's in key/value format.
 --
 -- >>> let ver = "11.1.0 (5a04ec7)"::ByteString
 -- >>> let strangeVer = "11'1&0@#$%,.:\"[]{}?+^()=asdfqwer"::ByteString
@@ -496,15 +497,25 @@ readPGRSTEnvironment =
 --
 -- >>> addFallbackAppName strangeVer "postgres:///postgres?host=server&port=5432"
 -- "postgres:///postgres?host=server&port=5432&fallback_application_name=PostgREST%2011%271%260%40%23%24%25%2C.%3A%22%5B%5D%7B%7D%3F%2B%5E%28%29%3Dasdfqwer"
+--
+-- Special chars in password
+-- >>> addFallbackAppName ver "postgres:///postgres:pass=()[]&#?host=server&port=5432"
+-- "postgres:///postgres:pass=()[]&#?host=server&port=5432&fallback_application_name=PostgREST%2011.1.0%20%285a04ec7%29"
 addFallbackAppName :: ByteString -> Text -> Text
 addFallbackAppName version dbUri = dbUri <>
-  case uriQuery <$> parseURI (toS dbUri) of
-    Nothing  -> " " <> keyValFmt -- Assume key/value connection string if the uri is not valid
-    Just ""  -> "?" <> uriFmt
-    Just "?" -> uriFmt
-    _        -> "&" <> uriFmt
+  if isPgURI dbUri
+    then case snd $ T.breakOn "?" dbUri of
+      "?" -> fallbackUriFmt
+      ""  -> "?" <> fallbackUriFmt
+      _   -> "&" <> fallbackUriFmt
+    else " " <> fallbackKeyValFmt
   where
-    uriFmt = pKeyWord <> toS (escapeURIString isUnescapedInURIComponent $ toS pgrstVer)
-    keyValFmt = pKeyWord <> "'" <> T.replace "'" "\\'" pgrstVer <> "'"
-    pKeyWord = "fallback_application_name="
+    fallbackUriFmt    = key <> toS (escapeURIString isUnescapedInURIComponent $ toS pgrstVer)
+    fallbackKeyValFmt = key <> "'" <> T.replace "'" "\\'" pgrstVer <> "'"
+    key = "fallback_application_name="
     pgrstVer = "PostgREST " <> T.decodeUtf8 version
+    isPgURI str =
+      let
+        uriDesignator = "postgresql://"
+        shortUriDesignator = "postgres://" in
+      uriDesignator `T.isPrefixOf` str || shortUriDesignator `T.isPrefixOf` str