teach API to slice modal times of days

Expand glob patterns to regexps, optimally, the fast prefix kind.
For @jasoncalabrese, @stavior, @kenstack and friends. :-)

lib/api/entries/index.js

@@ -3,6 +3,7 @@
 var consts = require('../../constants');
 var es = require('event-stream');
 var sgvdata = require('sgvdata');
+var expand = require('expand-braces');
 
 var ID_PATTERN = /^[a-f\d]{24}$/;
 function isId (value) {
@@ -245,6 +246,41 @@ function configure (app, wares, ctx) {
     });
     api.get('/echo/:echo/:model?/:spec?', echo_query);
 
+    function prep_patterns (req, res, next) {
+      var pattern = [ ];
+      if (req.params.prefix) {
+        pattern.push('^' + req.params.prefix);
+      }
+      if (req.params.regex) {
+        pattern.push('.*' + req.params.regex);
+      }
+      pattern = expand(pattern.join(''));
+      req.pattern = pattern;
+      var matches = pattern.map(function iter (pat) {
+            return new RegExp(pat);
+      });
+      var query = {
+        dateString: {
+          $in: matches
+        }
+      };
+
+      if (req.query.find) {
+        if (req.query.find.dateString) {
+          req.query.find.dateString.$in = query.dateString.$in;
+        } else {
+          req.query.find.dateString = query.dateString;
+        }
+      } else {
+        req.query.find = query;
+      }
+      next( );
+    }
+    api.get('/times/echo/:prefix?/:regex?', prep_patterns, function (req, res, next) {
+      res.json({ req: { params: req.params, query: req.query}, pattern: req.pattern});
+    });
+    api.get('/times/:prefix?/:regex?', prep_patterns, query_models, format_entries);
+
     // Allow previewing your post content, just echos everything you
     // posted back out.
     api.post('/entries/preview', function (req, res, next) {