Source code for the software projects route of my web server

software.rs

use accept_encoding::AcceptEncoding;
use cacher::{CachedContent, Page, PageCache};
use database::DBConnection;
use horrorshow::prelude::*;
use horrorshow::Template;
use rocket::State;
use rocket_contrib::Template as HandlebarTemplate;

macro_rules! request_content {
    ($cache:ident, $url:ident, $encoding:ident, $closure:expr) => {
        match $cache.request_content($url.clone(), $encoding) {
            Ok(content) => Ok(content),
            Err(action) => $cache.update_cache($url, action, $encoding, $closure)
        }
    }
}

#[get("/projects")]
pub fn software_projects (
    cache: State<PageCache>,
    conn: DBConnection,
    encoding: AcceptEncoding
) -> Result<CachedContent, String> {
    let url = String::from("/projects");

    request_content!(cache, url, encoding, || {
        let context = get_software_projects(&conn)?;
        Ok(Page::new(HandlebarTemplate::render("software_index", &context), encoding).into())
    })
}

#[derive(Serialize)]
pub struct PageContext {
    page: String
}

#[derive(FromForm, Serialize)]
pub struct SoftwareProject {
    pub name:        String,
    pub repo:        String,
    pub description: String,
    pub image:       Option<String>,
}

const GET_PROJECTS: &'static str = "SELECT
    name, repo, description, image
FROM software ORDER BY ranking";

pub fn get_software_projects(conn: &DBConnection) -> Result<PageContext, String> {
    let iterator = conn.get().query(GET_PROJECTS, &[]).map_err(|why| why.to_string())?;
    let iterator = iterator.iter()
        .map(|project| SoftwareProject {
            name:        project.get(0),
            repo:        project.get(1),
            description: project.get(2),
            image:       project.get(3),
        });

    let html = html! {
        @ for project in iterator {
            article {
                header {
                    @ if let Some(ref image) = project.image {
                        @ if !image.is_empty() {
                            img(src = image);
                        }
                    }
                    div(class = "name") {
                        : Raw(&project.name)
                    }
                    div(class = "repo") {
                        a(href = &project.repo) {
                            : Raw(&project.repo)
                        }
                    }
                }
                section {
                    p {
                        : Raw(&project.description)
                    }
                }
            }
        }
    };

    Ok(PageContext { page: html.into_string().unwrap_or_default() })
}