From b12373a1277e22670cd47b475b861a9b589e094b Mon Sep 17 00:00:00 2001
From: Sander van der Burg <svanderburg@gmail.com>
Date: Thu, 17 Aug 2017 22:03:30 +0200
Subject: [PATCH] - Add note on deploying a CLI project - Fix error when a
 project without dependencies (and lock file) is deployed

---
 README.md                         | 35 +++++++++++++++++++++++--------
 src/Composer2Nix/composer-env.nix | 27 ++++++++++++++----------
 2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/README.md b/README.md
index 2a9cdec..b93809c 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 composer2nix
 ============
-`composer2nix` is a tool that can be used to generate [Nix](http://nixos.org)
+`composer2nix` is a tool that can be used to generate [Nix](http://nixos.org/nix)
 expressions for PHP [composer](https://getcomposer.org) packages.
 
 Nix integration makes it possible to use the Nix package manager (as opposed to
@@ -29,10 +29,10 @@ including its dependencies:
 
     $ nix-build
 
-An example use case scenario
-============================
-We can use `composer2nix` to automate the deployment of a web application as
-part of a NixOS configuration.
+Deploying a web application project
+-----------------------------------
+We can use `composer2nix` to automate the deployment of a web application project
+as part of a NixOS configuration.
 
 For example, we can create the following trivial PHP web application
 (`index.php`) that uses the [dompdf](http://dompdf.github.io/) library to
@@ -82,9 +82,11 @@ application and its dependencies.
 We can use Nix to build a bundle of our web application including its
 dependencies:
 
+```bash
 $ nix-build
 $ ls result/
 index.php  vendor/
+```
 
 (As may be observed, the `vendor/` folder contains all dependency artifacts).
 
@@ -115,17 +117,32 @@ in
 
 We can deploy the above NixOS configuration as follows:
 
-    $ nixos-rebuild switch
+```bash
+$ nixos-rebuild switch
+```
 
 If the above command succeeds, we have a running system with the Apache
 webserver serving our web application.
 
+Deploying a command-line utility project
+----------------------------------------
+In addition to web applications, we can also deploy command-line utility
+projects implemented in PHP.
+
+For example, for the `composer2nix` project, we can generate a CLI-specific
+expression by adding the `--executable` parameter:
+
+    $ composer2nix --executable
+
+We can install the `composer2nix` executable in our Nix profile by running:
+
+    $ nix-env -f default.nix -i
+
 Limitations
 ===========
 Currently, the state of this tool is that it is just a proof on concept
-implementation. As a result, it is lacking many features and probably buggy.
-Most importantly, only the `path`, `zip`, `git`, and `hg` dependencies are
-supported.
+implementation. For example, it does not support downloading from `fossil`
+repositories.
 
 License
 =======
diff --git a/src/Composer2Nix/composer-env.nix b/src/Composer2Nix/composer-env.nix
index 8c6c961..7e6024c 100644
--- a/src/Composer2Nix/composer-env.nix
+++ b/src/Composer2Nix/composer-env.nix
@@ -57,19 +57,24 @@ rec {
         text = ''
           #! ${php}/bin/php
           <?php
-          $composerLockStr = file_get_contents($argv[1]);
-
-          if($composerLockStr === false)
+          if(file_exists($argv[1]))
           {
-              fwrite(STDERR, "Cannot open composer.lock contents\n");
-              exit(1);
+              $composerLockStr = file_get_contents($argv[1]);
+
+              if($composerLockStr === false)
+              {
+                  fwrite(STDERR, "Cannot open composer.lock contents\n");
+                  exit(1);
+              }
+              else
+              {
+                  $config = json_decode($composerLockStr);
+                  $packagesStr = json_encode($config->packages, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
+                  print($packagesStr);
+              }
           }
           else
-          {
-              $config = json_decode($composerLockStr);
-              $packagesStr = json_encode($config->packages, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
-              print($packagesStr);
-          }
+              print("[]");
           ?>
         '';
       };
@@ -170,7 +175,7 @@ rec {
 
         ${stdenv.lib.optionalString (removeComposerArtifacts) ''
           # Remove composer stuff
-          rm composer.json composer.lock
+          rm -f composer.json composer.lock
         ''}
     '';
   };