Add limited file attachment info functionality

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leo"
-version = "0.2.0"
+version = "0.3.0"
 authors = ["NGnius <ngniusness@gmail.com>"]
 edition = "2018"
 

src/commands.rs

@@ -1,5 +1,7 @@
 mod cmd_macro;
+mod cmd_preview;
 
 pub use self::{
     cmd_macro::CmdMacro,
+    cmd_preview::CmdPreview,
 };

src/commands/cmd_preview.rs

@@ -0,0 +1,101 @@
+extern crate serenity;
+use serenity::{
+    model::channel::Message,
+    model::channel::Attachment,
+    prelude::*,
+    utils::MessageBuilder,
+    utils::Colour,
+};
+
+extern crate regex;
+use regex::{Regex, RegexBuilder};
+
+use crate::traits::Command;
+
+pub struct CmdPreview {
+    format: Regex,
+    help_format: Regex,
+    extension_format: Regex,
+}
+
+impl Command for CmdPreview {
+    fn execute(&mut self, ctx: &Context, msg: &Message) {
+        for attachment in &msg.attachments {
+            if self.attachment_extension(&attachment) != "" {
+                if let Err(why) = msg.channel_id.send_message(&ctx.http, |m| {
+                    return m.embed(|e| {
+                        return e.colour(Colour::from_rgb(200, 200, 0))
+                            .title(self.title_attachment(&attachment))
+                            .description(self.describe_attachment(&attachment));
+                    });
+                }) {
+                    println!("Failed to send file preview message {:?}", why);
+                }
+            }
+        }
+    }
+
+    fn valid(&self, _ctx: &Context, msg: &Message) -> bool {
+        return self.format.is_match(&msg.content) && msg.attachments.len() != 0 && !msg.author.bot;
+    }
+
+    fn help(&self, ctx: &Context, msg:&Message) {
+        let mut response = MessageBuilder::new();
+        response.push("**Generate file attachment previews**\n*This has no standalone commands*");
+        if let Err(why) = msg.channel_id.say(&ctx.http, &response.build()) {
+            println!("Failed to send file preview help message {:?}", why);
+        }
+    }
+
+    fn valid_help(&self, _ctx: &Context, msg: &Message) -> bool {
+        return self.help_format.is_match(&msg.content);
+    }
+}
+
+impl CmdPreview {
+    pub fn new() -> CmdPreview {
+        return CmdPreview {
+            format:
+                RegexBuilder::new(r#".*"#)
+                    .multi_line(true)
+                    .case_insensitive(true)
+                    .build()
+                    .unwrap(),
+            help_format:
+                RegexBuilder::new(r#"^!help\s*(?:preview|file)"#)
+                    .case_insensitive(true)
+                    .build()
+                    .unwrap(),
+            extension_format:
+                RegexBuilder::new(r#"\.(dll|exe|so)$"#)
+                    .case_insensitive(true)
+                    .build()
+                    .unwrap(),
+        };
+    }
+
+    fn describe_attachment(&self, attachment: &Attachment) -> String {
+        let ext = self.attachment_extension(attachment);
+        if ext == "dll" {
+            return "Microsoft Windows **__D__ynamic __L__ink __L__ibrary**\nPlease make sure you trust who sent this before downloading this file.".to_string();
+        } else if ext == "exe" {
+            return "Microsoft Windows **__Exe__cutable**\nPlease make sure you trust who sent this before downloading or running this file.".to_string();
+        } else if ext == "so" {
+            return "Generic Operating System **__S__hared (__O__bject) Library**\nPlease make sure you trust who sent this before downloading or running this file.".to_string();
+        }
+        return "".to_string();
+    }
+
+    fn title_attachment(&self, attachment: &Attachment) -> String {
+        return attachment.filename.to_uppercase();
+    }
+
+    fn attachment_extension(&self, attachment: &Attachment) -> String {
+        if let Some(parsed) = self.extension_format.captures(&attachment.filename) {
+            if let Some(ext) = parsed.get(1) {
+                return ext.as_str().to_lowercase().to_string();
+            }
+        }
+        return "".to_string();
+    }
+}

src/main.rs

@@ -67,6 +67,7 @@ fn main() {
     // register commands;
     let mut commands = std::vec::Vec::<Box<dyn traits::Command>>::new();
     commands.push(Box::new(commands::CmdMacro::new()));
+    commands.push(Box::new(commands::CmdPreview::new()));
     // start bot
     let mut client = Client::new(&token, event_handler).expect("Error creating client");
     {