Configuring MS4W and MapCache for use in OpenLayers 3

This was spawned by an MS4W user asking how to setup OpenLayers3 for an MS4W MapCache's WMS service (​thread), with the following incorrect Javascript code, which did not write tiles to MS4W's cache directory:

new ol.layer.Tile({
title: 'Chabahar',    
source: new ol.source.TileWMS({
url: 'http://localhost:100/cgi-bin/mapserv.exe?map=D:/WEB_GIS/code_test/wms/HTML5Application/public_html/chabahar.map&',
params: {
    'LAYERS': 'chabahar',
    'FORMAT': 'image/png',
    'TILED': true
},
serverType: 'mapserver'
})
                                        })  ,

Step 1: Initialize MapCache Module

• follow all of the steps in MS4W's ​README to initialize the MapCache module
• confirm that tiles are being generated inside the folder: /ms4w/tmp/ms_tmp/cache/

Step 2: Install MS4W's OpenLayers3 Package

• if you haven't installed MS4W's OpenLayers 3 package (we'll use its sample WMS mapfile), please install it:
  • save the OpenLayers zip locally from: ​http://ms4w.com/download.html#applications-packaged-for-ms4w
  • extract its contents to the root of your MS4W installation
  • restart Apache: as Administrator, execute: /ms4w/apache-restart.bat
  • on your MS4W homepage, click on the "MapServer WMS Example" link, in the OpenLayers section
  • this example uses a local WMS service, it should display the world countries as below:

Step 3: Configure mapcache.xml to use this WMS as a Source

• add the following to your mapcache.xml file (and if necessary change the <url> and <map> paths):

  <source name="ms4wserver" type="wms">
    <http>
      <url>http://127.0.0.1/cgi-bin/mapserv.exe</url>
    </http>
    <getmap>
      <params>
        <map>C:/ms4w/apps/openlayers-3.15.1/examples/map/wms-server.map</map>
        <layers>countries</layers>
      </params>
    </getmap>
  </source> 
  

• edit the existing <tileset> section of mapcache.xml, so that it includes:

  <tileset name="test">
    <source>ms4wserver</source>
    <cache>disk</cache>
    <grid>GoogleMapsCompatible</grid>
    <format>PNG</format>
    <metatile>5 5</metatile>
    <metabuffer>10</metabuffer>
    <expires>3600</expires>
  </tileset>
  

  • we use the "GoogleMapsCompatible" grid here, because OpenLayers assumes EPSG:3875. Read more about the various "Preconfigured Grids" for MapCache at: ​http://www.mapserver.org/mapcache/config.html#grid