implement store-snapshot in snapshot package.

This feature provides the ability to unzip a .zip file (the expected file format
users must upload Snapshots with) and store the contents of the .zip file in the
/snapshots directory.

src/snapshot.lisp

@@ -7,7 +7,8 @@
   (:export
    #:take-snapshot
    #:restore-from-snapshot
-   #:delete-snapshot))
+   #:delete-snapshot
+   #:store-snapshot))
 (in-package #:snapshot)
 
 (defun take-snapshot ()
@@ -37,3 +38,25 @@ user can repopulate that database after they have restored this website. The
 (defun delete-snapshot (snapshot-name)
   "Deletes the snapshot in the /snapshots directory with `SNAPSHOT-NAME'."
   (storage:remove-raw-directory (format nil "snapshots/~a/" snapshot-name)))
+
+(defun store-snapshot (filename data)
+  "Unzips `SNAPSHOT-FILE' and stores it in /snapshots directory.
+
+The .zip file is deleted after it has been un-zipped. I did think about moving
+the zipped version of the file into the /storage/media directory but there is
+too much second guessing going on. I found I was uploading .zip files from the
+/storage/media directory and I don't know if users will be uploading .zip files
+they had just downloaded from /storage/media. If that is the case, then there
+is:
+
+a.) No need to move it to /storage/madia;
+b.) Extra work regarding checks for duplicate entries; and,
+c.) I don't know if that is too much 'magic' for users and cause confusion.
+
+If the user is in a paniced state -- trying to restore their website, confusion
+is the thing I want to keep to a minimum for them."
+  (storage:store-with-raw-path (format nil "snapshots/~a" filename) data)
+  (zip:unzip (storage:make-raw-path (format nil"snapshots/~a" filename))
+             (storage:make-raw-path (format nil "snapshots/~a/"
+                                            (pathname-name filename))))
+  (storage:remove-file-with-raw-path (format nil "snapshots/~a" filename)))