From b8a4926107f273c1606a026687ebfcc74da147d4 Mon Sep 17 00:00:00 2001
From: Paul Duncan <pabs@pablotron.org>
Date: Mon, 7 Mar 2016 03:50:09 -0500
Subject: refactor get_posts

---
 src/guff/api-methods.cr | 24 ++++++++----
 src/guff/post-model.cr  | 98 ++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 93 insertions(+), 29 deletions(-)

diff --git a/src/guff/api-methods.cr b/src/guff/api-methods.cr
index 859e7ce..d8d1c44 100644
--- a/src/guff/api-methods.cr
+++ b/src/guff/api-methods.cr
@@ -36,6 +36,12 @@ module Guff
               required: false,
               default:  "date,desc",
             },
+
+            "cols": {
+              text:     "Column list",
+              type:     :text,
+              required: false,
+            },
           },
         },
 
@@ -296,17 +302,21 @@ module Guff
         # get value
         val = if arg_data[:required]
           params.fetch(arg_name)
-        else
+        elsif arg_data[:default]
           params.fetch(arg_name, arg_data[:default] as String)
+        else
+          nil
         end
 
-        # check value
-        if !TYPE_CHECKS[arg_data[:type]].match(val)
-          raise "invalid parameter format: %s" % [arg_name]
-        end
+        if val
+          # check value
+          if !TYPE_CHECKS[arg_data[:type]].match(val)
+            raise "invalid parameter format: %s" % [arg_name]
+          end
 
-        # add value to result
-        r[arg_name] = val
+          # add value to result
+          r[arg_name] = val
+        end
 
         # return result
         r
diff --git a/src/guff/post-model.cr b/src/guff/post-model.cr
index 4a3f406..46e2dca 100644
--- a/src/guff/post-model.cr
+++ b/src/guff/post-model.cr
@@ -30,19 +30,7 @@ module Guff
       ",
 
       get_posts: "
-        SELECT a.post_id,
-               a.site_id,
-               a.name,
-               a.body,
-               a.html,
-
-               (SELECT group_agg(d.name, '|')
-
-                  FROM post_tags c
-                  JOIN tags d
-                    ON (d.tag_id = c.tag_id)
-
-                 WHERE d.post_id = a.post_id) AS tags
+        SELECT %{cols}
 
           FROM posts a
           JOIN (%{tags}) b
@@ -60,11 +48,64 @@ module Guff
       super(models, SQL)
     end
 
-    SORTS = {
-      "posted_at": "a.posted_at",
+    COLUMNS = {
+      "post_id": {
+        default:  true,
+        sortable: true,
+        clause:   "a.post_id",
+      },
+
+      "name": {
+        default:  true,
+        sortable: true,
+        clause:   "a.name",
+      },
+
+      "body": {
+        default:  false,
+        sortable: true,
+        clause:   "a.body",
+      },
+
+      "html": {
+        default:  true,
+        sortable: true,
+        clause:   "a.html",
+      },
+
+      "posted_at": {
+        default:  true,
+        sortable: true,
+        clause:   "a.posted_at",
+      },
+
+      "created_at": {
+        default:  true,
+        sortable: true,
+        clause:   "a.created_at",
+      },
+
+      "tags": {
+        default:  true,
+        sortable: false,
+        clause:   "
+          (SELECT group_agg(d.name, '|')
+
+             FROM post_tags c
+             JOIN tags d
+               ON (d.tag_id = c.tag_id)
+
+            WHERE d.post_id = a.post_id)
+        ",
+      },
     }
 
+    #####################
+    # get_posts methods #
+    #####################
+
     def get_posts(
+      cols = nil                  : Array(String)?,
       site_id = nil               : Int?,
       q = ""                      : String,
       tags = [] of Array(String)  : Array(Array(String)),
@@ -78,15 +119,18 @@ module Guff
         "site_id": (site_id || @models.site.get_default).to_s,
       } of String => String
 
-      p tags
+      # verify sort column
+      raise "unknown sort column" unless COLUMNS.has_key?(sort)
+      raise "column is not sortable" unless COLUMNS[sort][:sortable]
 
       # build tmpl args
       tmpl_args = {
         # TODO
         "filter":   "1 = 1", # true
-        "sort":     SORTS[sort],
+        "sort":     COLUMNS[sort][:col],
         "dir":      dir,
         "tags":     get_tags_filter(tags),
+        "cols":     get_columns_clause(cols),
       } of String => String
 
       # count number of matching rows
@@ -113,6 +157,20 @@ module Guff
       )
     end
 
+    private def get_columns_clause(cols : Array(String)?)
+      (cols || COLUMNS.keys.select { |col|
+        COLUMNS[key][:default]
+      }).map { |col|
+        "%s AS %s" % [COLUMNS[col][:clause], col]
+      }.join(", ")
+    end
+
+    NO_POSTS = "
+      SELECT post_id
+        FROM posts
+       LIMIT 0
+    "
+
     private def get_tags_filter(tag_sets : Array(Array(String)))
       p tag_sets
       (tag_sets.size > 0) ? template(:tags, {
@@ -125,11 +183,7 @@ module Guff
             }.join(" INTERSECTS "),
           })
         }.join(" UNION "),
-      }) : "
-        SELECT post_id
-          FROM posts
-         LIMIT 0
-      "
+      }) : NO_POSTS
     end
 
     def add_post(req)
-- 
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