Unique canvas name suppor

c-historico/handler.cr

@@ -3,8 +3,38 @@ require "http/headers"
 require "http/request"
 require "ishi/html"
 require "json"
+require "uuid"
 
 class Handler
+  def format_buffer(buffer, canvas_name)
+    # Process the gnuplot output so it works in the page
+    #
+    # buffer is the Ishi output
+    # name is a string to replace for gnuplot_canvas so
+    # we can have multiple charts in a page
+
+    html = buffer.to_s.split("\n")
+    html = html[html.index("<script type=\"text/javascript\">")..html.index("</script>")]
+    html = html.join("\n") + %(
+    <div class="gnuplot">
+    <canvas id="Tile" width="32" height="32" hidden></canvas>
+    <table class="plot">
+    <tr><td>
+    <canvas id="gnuplot_canvas" width="800" height="300" tabindex="0">
+    Sorry, your browser seems not to support the HTML 5 canvas element
+    </canvas>
+    </td></tr>
+    </table>
+    <script type="text/javascript" defer>
+    gnuplot.init(); gnuplot_canvas();
+    </script>
+    </div>
+    )
+    # This ID needs to be unique in case 
+    # we have 2 charts in the same page
+    html.gsub("gnuplot_canvas", canvas_name)
+  end
+
   def query(sql)
     params = URI::Params.encode({"q": sql})
     response = HTTP::Client.get URI.new(
@@ -70,27 +100,8 @@ class Handler
       }
     end
 
-    # This is a whole page, we just need some bits
-    html = buffer.to_s.split("\n")
-    html = html[html.index("<script type=\"text/javascript\">")..html.index("</script>")]
-    html = html.join("\n") + %(
-<div class="gnuplot">
-<canvas id="Tile" width="32" height="32" hidden></canvas>
-<table class="plot">
-<tr><td>
-    <canvas id="gnuplot_canvas" width="800" height="300" tabindex="0">
-	Sorry, your browser seems not to support the HTML 5 canvas element
-    </canvas>
-</td></tr>
-</table>
-<script type="text/javascript" defer>
-gnuplot.init(); gnuplot_canvas();
-</script>
-</div>
-)
-
     {
-      body:        html,
+      body:        format_buffer(buffer, "historico"),
       status_code: 200,
       headers:     HTTP::Headers{"Content-Type" => "text/html"},
     }