start with list-templates command

Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 log = "0.4"
 stderrlog = "0.4"
 structopt = "0.3"
+reqwest = { version = "0.10", features = ["blocking", "json"] }
 
 [target.'cfg(unix)'.dependencies]
 libc = "0.2"

src/app.rs

@@ -5,6 +5,8 @@
 use std::path::PathBuf;
 
 // 3rd-party crate imports
+use reqwest::blocking::Client;
+use reqwest::header::{ACCEPT, CONTENT_TYPE, USER_AGENT};
 use structopt::StructOpt;
 
 use log::{debug, error, info, trace, warn};
@@ -16,6 +18,7 @@ use crate::helpers::{git_dir, BoilerplateOpts, HELP_TEMPLATE};
 
 /// The verbosity level when no `-q` or `-v` arguments are given, with `0` being `-q`
 pub const DEFAULT_VERBOSITY: u64 = 1;
+pub const DEFAULT_USER_AGENT: &str = "gitig";
 
 /// Command-line argument schema
 ///
@@ -68,6 +71,8 @@ pub enum Command {
         /// The language for which the gitignore should be downloaded
         lang: String,
     },
+    /// List all available templates that can be downloaded
+    ListTemplates,
 }
 
 /// Runs the command `add`
@@ -92,11 +97,28 @@ fn run_get(lang: &str) -> Result<()> {
     unimplemented!();
 }
 
+/// Runs the command `list-templates`
+fn run_list_templates() -> Result<()> {
+    let client = Client::new();
+    let mut res = client
+        .get("https://api.github.com/repos/github/gitignore/contents//")
+        .header(ACCEPT, "application/jsonapplication/vnd.github.v3+json")
+        .header(CONTENT_TYPE, "application/json")
+        .header(USER_AGENT, format!("{} {}", DEFAULT_USER_AGENT, env!("CARGO_PKG_VERSION")))
+        .send()
+        .chain_err(|| "Error while sending request to query all templates")?;
+    println!("{:?}", &res);
+    let body = res.text().chain_err(|| "json")?;
+    println!("{:?}", &body);
+    Ok(())
+}
+
 /// The actual `main()`
 pub fn main(opts: CliOpts) -> Result<()> {
     match opts.cmd {
         Command::Add { glob } => run_add(&glob)?,
         Command::Get { lang } => run_get(&lang)?,
+        Command::ListTemplates => run_list_templates()?,
     };
 
     Ok(())

src/main.rs

@@ -25,6 +25,8 @@ This project used [rust-cli-boilerplate](https://github.com/ssokolow/rust-cli-bo
 #[macro_use]
 extern crate error_chain;
 
+extern crate reqwest;
+
 // stdlib imports
 use std::convert::TryInto;
 use std::io;