Configuring MongoDB in a Clojure Luminus web framework

clojure, luminus, mongodb

Solution

I followed your steps and created new Luminus project using luminus template.

I also studied generated code an found, that default home page is 100% static. So, it shows `MongoDB Configuration is Required` regardless of whether it actually configured or not:

(defn home-page []
  (layout/render
    "home.html" {:content (util/md->html "/md/docs.md")}))

In other words, it just renders `resources/public/md/docs.md` into `.html` and shows it, always the same html page.

As for your configuration, it's absolutely fine.

As for your `user.html` page, the actual problem is that `id` in `user-page` route is a string, while `_id` in your database is a number. So, instead of `(get-replies 2)` you're calling `(get-replies "2")`. Try using stringified `_id`s, or parse incoming `id`s with `read-string` function or `Long/parseLong` first:

(defn user-page [& [id]]
  (layout/render "user.html"
                 {:id id
                  :replies (-> id
                               Long/parseLong ; throws NumberFormatException
                               project-db/get-replies)}))

I would recommend using stringified `_id`s, because it's easier and safer than parsing strings into numbers.

Problem

I am having issues configuring a MongoDB database inside a Luminus project. This should be pretty straightforward given the lein templates: https://github.com/yogthos/luminus-template. Typing `lein new luminus <name> +mongodb` will give you a default mongoDB setup which is the file: `src/app-name/db/core.clj` To run the server, type `lein ring server` which should open a web browser and point it to `localhost:3000` by default. A default home page will be displayed, and for me, it tells me that "MongoDB configuration is Required." It tells me that I can configure it in the same file: `src/app-name/db/core.clj.` I have tried a number of different things, but what I am currently trying and what makes the most sense to me is the following: ``` (defonce coll "collection-name") (defonce db (let [uri "mongodb://127.0.0.1/db-name" {:keys [conn db]} (mg/connect-via-uri uri)] db)) ``` Unfortunately, when I connect my browser, I still get the same "MongoDB configuration is Required" message. I have also tried using CURL and various HTTP routes defined in my application that access the database without success. What is odd though, is that this works in the REPL. EDIT: To be more clear, here is the example in the REPL: ``` clj-project-name.db.core> (get-replies 2) ["mew-mew" [1.0 "hello"]] ``` In the code I have the following pieces: ``` (ns clj-project-name.routes.home (:require [compojure.core :refer :all] [clj-project-name.layout :as layout] [clj-project-name.util :as util] [clj-project-name.db.core :as project-db])) (defn get-replies [id] (mc/distinct db coll "replies" {:_id id})) (GET "/user" [id] (user-page id)) ; defined in home-routes inside namespace clj-project-name.routes.home (defn user-page [& [id]] ;defined inside namespace clj-project-name.routes.home (layout/render "user.html" {:id id :replies (projectl-db/get-replies id)})) <h1>User {{id}}'s page</h1> ; part of the HTML template <p> <b>Replies:</b> {{replies}} </p> ``` Here is the page loaded in the browser: As we can see, the `replies` list is empty, when it should be `["mew-mew" [1.0 "hello"]]` as we saw in the REPL. EDIT: Another oddity is that just when the browser is loaded after typing `lein ring server` I can see the following output from `mongodb` in the terminal: ``` 2014-12-02T21:16:57.941-0500 [initandlisten] connection accepted from 127.0.0.1:38854 #28 (5 connections now open). ``` What else can I do to get connected to MongoDB? Thanks for your help.

Original source