From 2f432cbb6d38569759e12a2cbe80ec9dce4b2f25 Mon Sep 17 00:00:00 2001 From: "okbob@github.com" Date: Mon, 24 Jul 2023 20:18:16 +0200 Subject: [PATCH 4/4] Implementation of %N prompt placeholder It is based on forcing reporting feature"role" GUC to client. --- doc/src/sgml/ref/psql-ref.sgml | 19 ++++++++++++++++++- src/bin/psql/command.c | 13 +++++++++++++ src/bin/psql/prompt.c | 27 +++++++++++++++++++++++++++ src/bin/psql/settings.h | 1 + src/bin/psql/startup.c | 32 ++++++++++++++++++++++++++++++++ 5 files changed, 91 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml index d94e3cacfc..8b267a6da6 100644 --- a/doc/src/sgml/ref/psql-ref.sgml +++ b/doc/src/sgml/ref/psql-ref.sgml @@ -4568,7 +4568,24 @@ testdb=> INSERT INTO my_table VALUES (:'content'); The port number at which the database server is listening. - + + %N + + + The database role name. This value is specified by command + SET ROLE. Until execution of this command + the value is set to the database session user name. + + + + This substitution requires PostgreSQL + version 16 and up. When you use older version, the empty string + is used instead. + + + + + %n diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c index bcd8eb3538..bad0fdf415 100644 --- a/src/bin/psql/command.c +++ b/src/bin/psql/command.c @@ -3883,6 +3883,7 @@ SyncVariables(void) { char vbuf[32]; const char *server_version; + PGresult *result; /* get stuff from connection */ pset.encoding = PQclientEncoding(pset.db); @@ -3912,6 +3913,18 @@ SyncVariables(void) /* send stuff to it, too */ PQsetErrorVerbosity(pset.db, pset.verbosity); PQsetErrorContextVisibility(pset.db, pset.show_context); + + /* link role GUC when it is needed for prompt */ + if (pset.prompt_shows_role) + result = PQlinkParameterStatus(pset.db, "role"); + else + result = PQunlinkParameterStatus(pset.db, "role"); + + if (PQresultStatus(result) != PGRES_COMMAND_OK) + pg_log_info("cannot set REPORT flag on configuration variable \"role\": %s", + PQerrorMessage(pset.db)); + + PQclear(result); } /* diff --git a/src/bin/psql/prompt.c b/src/bin/psql/prompt.c index 969cd9908e..566b47d814 100644 --- a/src/bin/psql/prompt.c +++ b/src/bin/psql/prompt.c @@ -165,6 +165,33 @@ get_prompt(promptStatus_t status, ConditionalStack cstack) if (pset.db) strlcpy(buf, session_username(), sizeof(buf)); break; + /* DB server user role */ + case 'N': + if (pset.db) + { + const char *rolename = NULL; + + /* + * This feature requires GUC "role" to be marked + * by GUC_REPORT flag. This is done by PQlinkParameterStatus + * function. This function requires protocol 3.1 (ReportGUC + * message). Fallback is empty string. + */ + if (PQprotocolVersionFull(pset.db) >= PQmakeProtocolVersionFull(3,1)) + { + rolename = PQparameterStatus(pset.db, "role"); + + /* fallback when role is not set yet */ + if (rolename && strcmp(rolename, "none") == 0) + rolename = session_username(); + } + + if (rolename) + strlcpy(buf, rolename, sizeof(buf)); + else + buf[0] = '\0'; + } + break; /* backend pid */ case 'p': if (pset.db) diff --git a/src/bin/psql/settings.h b/src/bin/psql/settings.h index 1106954236..cb7c12bd1d 100644 --- a/src/bin/psql/settings.h +++ b/src/bin/psql/settings.h @@ -154,6 +154,7 @@ typedef struct _psqlSettings PGVerbosity verbosity; /* current error verbosity level */ bool show_all_results; PGContextVisibility show_context; /* current context display level */ + bool prompt_shows_role; } PsqlSettings; extern PsqlSettings pset; diff --git a/src/bin/psql/startup.c b/src/bin/psql/startup.c index 5a28b6f713..0dac396525 100644 --- a/src/bin/psql/startup.c +++ b/src/bin/psql/startup.c @@ -1094,10 +1094,40 @@ histcontrol_hook(const char *newval) return true; } +static void +prompt_needs_role_parameter_status(void) +{ + PGresult *result; + + if (!pset.db) + return; + + pset.prompt_shows_role = false; + + if (pset.prompt1 && strstr(pset.prompt1, "%N")) + pset.prompt_shows_role = true; + else if (pset.prompt2 && strstr(pset.prompt2, "%N")) + pset.prompt_shows_role = true; + else if (pset.prompt3 && strstr(pset.prompt3, "%N")) + pset.prompt_shows_role = true; + + if (pset.prompt_shows_role) + result = PQlinkParameterStatus(pset.db, "role"); + else + result = PQunlinkParameterStatus(pset.db, "role"); + + if (PQresultStatus(result) != PGRES_COMMAND_OK) + pg_log_info("cannot set REPORT flag on configuration variable \"role\": %s", + PQerrorMessage(pset.db)); + + PQclear(result); +} + static bool prompt1_hook(const char *newval) { pset.prompt1 = newval ? newval : ""; + prompt_needs_role_parameter_status(); return true; } @@ -1105,6 +1135,7 @@ static bool prompt2_hook(const char *newval) { pset.prompt2 = newval ? newval : ""; + prompt_needs_role_parameter_status(); return true; } @@ -1112,6 +1143,7 @@ static bool prompt3_hook(const char *newval) { pset.prompt3 = newval ? newval : ""; + prompt_needs_role_parameter_status(); return true; } -- 2.41.0