Implement Slack posting

rgwood · Nov 29, 2021 · 6de0235 · 6de0235
1 parent 22a4805
commit 6de0235
Showing 1 changed file with 48 additions and 5 deletions.
diff --git a/RezoningScraper/Program.cs b/RezoningScraper/Program.cs
@@ -3,6 +3,8 @@
 using System.CommandLine.Invocation;
 using System.Diagnostics;
 using System.Reflection;
+using System.Text;
+using System.Text.Json;
 using static Spectre.Console.AnsiConsole;
 
 namespace RezoningScraper;
@@ -15,17 +17,18 @@ static async Task<int> Main(string[] args)
         var rootCommand = new RootCommand("A tool to detect new+modified postings on Vancouver's shapeyourcity.ca website. Data is stored in a local SQLite database next to the executable.")
         {
             new Option<string?>("--slack-webhook-url",
+                getDefaultValue: () => "",
                 description: "A Slack Incoming Webhook URL. If specified, RezoningScraper will post info about new+modified rezonings to this address."),
         };
 
-        rootCommand.Handler = CommandHandler.Create<string?>(RunScraper);
+        rootCommand.Handler = CommandHandler.Create<string>(RunScraper);
         return await rootCommand.InvokeAsync(args);
     }
 
-    static async Task RunScraper(string? slackWebhookUri)
+    static async Task RunScraper(string slackWebhookUrl)
     {
         MarkupLine($"[green]Welcome to RezoningScraper v{Assembly.GetExecutingAssembly().GetName().Version}[/]");
-        if(string.IsNullOrEmpty(slackWebhookUri)) { WriteLine($"Slack URI not specified; will not publish updates to Slack."); }
+        if(string.IsNullOrWhiteSpace(slackWebhookUrl)) { WriteLine($"Slack URI not specified; will not publish updates to Slack."); }
         WriteLine();
 
         // Use Spectre.Console's Status UI https://spectreconsole.net/live/status
@@ -74,9 +77,9 @@ await AnsiConsole.Status().StartAsync("Opening DB...", async ctx =>
                 MarkupLine($"Upserted {latestProjects.Count} projects to the DB in [yellow]{stopwatch.ElapsedMilliseconds}ms[/]");
                 MarkupLine($"Found [green]{newProjects.Count}[/] new projects and [green]{changedProjects.Count}[/] modified projects.");
 
-                if (!string.IsNullOrEmpty(slackWebhookUri))
+                if (!string.IsNullOrEmpty(slackWebhookUrl) && (newProjects.Any() || changedProjects.Any()))
                 {
-                    // TODO: post changes to Slack
+                    await PostToSlack(slackWebhookUrl, newProjects, changedProjects);
                 }
 
                 PrintNewProjects(newProjects);
@@ -90,6 +93,46 @@ await AnsiConsole.Status().StartAsync("Opening DB...", async ctx =>
         });
     }
 
+    private static async Task PostToSlack(string slackWebhookUri, List<Project> newProjects, List<ChangedProject> changedProjects)
+    {
+        WriteLine($"Posting to Slack...");
+
+        var message = new StringBuilder();
+
+        foreach (var proj in newProjects)
+        {
+            message.AppendLine($"New: *<{proj.links!.self!}|{proj.attributes!.name!}>*\n");
+        }
+
+        foreach (var changedProject in changedProjects)
+        {
+            message.AppendLine($"Changed: *<{changedProject.LatestVersion.links!.self!}|{changedProject.LatestVersion.attributes!.name!}>*\n");
+
+            foreach (var change in changedProject.Changes)
+            {
+                const int MaxLength = 100; // arbitrary; we just need some way to avoid huuuuuuuge descriptions that look bad in Slack
+                if (change.Value.OldValue?.Length > MaxLength || change.Value.NewValue?.Length > MaxLength)
+                {
+                    message.AppendLine($"    {Capitalize(change.Key)} changed, too big to show");
+                }
+                else
+                {
+                    message.AppendLine($"    {Capitalize(change.Key)}: {change.Value.OldValue} ➡️ {change.Value.NewValue}");
+                }
+
+                string Capitalize(string str) => str.Substring(0, 1).ToUpper() + str.Substring(1);
+
+            }
+        }
+
+        var json = JsonSerializer.Serialize(new { text = message.ToString() });
+        var client = new HttpClient();
+        var content = new StringContent(json, Encoding.UTF8, "application/json");
+
+        await client.PostAsync(slackWebhookUri, content);
+        WriteLine("Posted new+changed projects to Slack");
+    }
+
     static void PrintNewProjects(List<Project> newProjects)
     {
         if (newProjects.Count == 0) return;