From ddc6bee3757d3e68a14fafdc47eb5d0a0ba923bb Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Sat, 23 Sep 2023 21:26:06 +0100
Subject: Got a working test connecting to postgres server and reading data.
 Added a couple more message types to facilitate this.

---
 src/conn.zig | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 80 insertions(+), 14 deletions(-)

(limited to 'src/conn.zig')

diff --git a/src/conn.zig b/src/conn.zig
index 870ab01..36c89df 100644
--- a/src/conn.zig
+++ b/src/conn.zig
@@ -1,10 +1,17 @@
 const std = @import("std");
+const log = std.log.scoped(.pgz);
 const SSHashMap = std.StringHashMap([]const u8);
 const Config = @import("config.zig");
 const StartupMessage = @import("startup_message.zig");
-const AuthenticationOk = @import("authentication_ok.zig");
-const AuthenticationCleartextPassword = @import("authentication_cleartext_password.zig");
 const ErrorResponse = @import("error_response.zig");
+const AuthenticationRequest = @import("authentication_request.zig");
+const ReadyForQuery = @import("ready_for_query.zig");
+const ParameterStatus = @import("parameter_status.zig");
+const BackendKeyData = @import("backend_key_data.zig");
+const read_message = @import("main.zig").read_message;
+const ProtocolError = @import("main.zig").ProtocolError;
+const ServerError = @import("main.zig").ServerError;
+const diagnosticReader = @import("main.zig").diagnosticReader;
 
 const Conn = @This();
 
@@ -18,7 +25,7 @@ const ConnStatus = enum {
 
 stream: std.net.Stream,
 config: Config,
-status: ConnStatus,
+status: ConnStatus = .connStatusUninitialized,
 
 pub fn connect(config: Config) !Conn {
     const allocator = config.allocator;
@@ -26,24 +33,83 @@ pub fn connect(config: Config) !Conn {
         .net => |addr| try std.net.tcpConnectToAddress(addr),
         .unix => |path| try std.net.connectUnixSocket(path),
     };
+    var res = Conn{
+        .stream = stream,
+        .config = config,
+    };
+    errdefer res.deinit();
     var writer = stream.writer();
-
-    errdefer stream.close();
+    var dr = diagnosticReader(10000, stream.reader());
+    var reader = dr.reader();
     var params = SSHashMap.init(allocator);
-    errdefer params.deinit();
     try params.put("user", config.user);
-    if (config.database) |database| try params.put(database);
+    if (config.database) |database| try params.put("database", database);
     var sm = StartupMessage{
         .parameters = params,
     };
     defer sm.deinit(allocator);
     try sm.write(allocator, writer);
+    lp: while (true) {
+        const response_type = try reader.readByte();
+        switch (response_type) {
+            ErrorResponse.Tag => {
+                var err = try read_message(ErrorResponse, allocator, reader);
+                defer err.deinit(allocator);
+                log.err("Error connecting to server {any}", .{err});
+                return ServerError.ErrorResponse;
+            },
+            AuthenticationRequest.Tag => {
+                var ar = try read_message(AuthenticationRequest, allocator, reader);
+                defer ar.deinit(allocator);
+                // TODO handle the authentication request
+                log.info("authentication request", .{});
+            },
+            ReadyForQuery.Tag => {
+                var rfq = try read_message(ReadyForQuery, allocator, reader);
+                defer rfq.deinit(allocator);
+                // TODO do something about transaction state?
+                res.status = .connStatusIdle;
+                log.info("ready for query", .{});
+                break :lp;
+            },
+            ParameterStatus.Tag => {
+                var ps = try read_message(ParameterStatus, allocator, reader);
+                defer ps.deinit(allocator);
+                // TODO Handle this somehow?
+                log.info("ParameterStatus: {s}:{s}", .{ps.name, ps.value});
+            },
+            BackendKeyData.Tag =>{
+                var bkd = try read_message(BackendKeyData, allocator, reader);
+                defer bkd.deinit(allocator);
+                log.info("BackendKeyData process_id {} secret_key {}" , .{bkd.process_id, bkd.secret_key});
+            },
+            else => {
+                log.err("unhandled message type [{c}]", .{response_type});
+                const diag = try dr.get(allocator);
+                defer allocator.free(diag);
+                log.err("diag [{s}]", .{diag});
+                return ProtocolError.WrongMessageType;
+            },
+        }
+    }
+    return res;
+}
+
+fn deinit(self: *Conn) void {
+    self.stream.close();
+}
+
+test "connect" {
+    // must have a local postgres runnning
+    // TODO maybe use docker to start one?
+    const allocator = std.testing.allocator;
+    const cfg = Config{
+        .allocator = allocator,
+        .address = .{.unix = "/run/postgresql/.s.PGSQL.5432"},
+        .database = "martin",
+        .user = "martin",
+    };
+    var conn = try Conn.connect(cfg);
+    defer conn.deinit();
 }
 
-const StartupMessageResponseType = enum(u8) {
-    ErrorResponse = 'E',
-    AuthenticationResponse = AuthenticationOk.Tag, // All the authentication responses share a message type and must be decoded by the next field
-};
-const StartupMessageResponse = union(StartupMessageResponseType) {
-    error: ErrorResponse,
-};
\ No newline at end of file
-- 
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