Openlayers 4 - Load WMS image layer require authen

2019-07-27 02:31发布

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I try to load WMS image layer with openlayers 4.6 and angular 5, the code is:

const syr_layer = new ol_layer_Image({
  source: new ol_source_ImageWMS({
      url: 'serverurl', crossOrigin: 'anonymous', serverType: 'geoserver',
      params: { 'LAYERS': 'tst:syr'},
      projection: 'EPSG:4326'
    });
});

But it throws an error:

GET (myserverurl) 401 (An Authentication object was not found in the SecurityContext)

How can I send authentication header with the GET request sent by openlayers?

2条回答
等我变得足够好
2楼-- · 2019-07-27 03:00

Thanks @Thomas, your answer isn't correct 100% but it clear the way for me to get the correct answer.

This is the tileLoader function that worked for me:

private tileLoader(tile, src) {
  const client = new XMLHttpRequest();

  client.open('GET', src);
  client.responseType = 'arraybuffer';
  client.setRequestHeader('Authorization', 'Basic ' + btoa(user + ':' + pass));

  client.onload = function () {
    const arrayBufferView = new Uint8Array(this.response);
    const blob = new Blob([arrayBufferView], { type: 'image/png' });
    const urlCreator = window.URL || (window as any).webkitURL;
    const imageUrl = urlCreator.createObjectURL(blob);
    tile.getImage().src = imageUrl;
  };

  client.send();
}
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疯言疯语
3楼-- · 2019-07-27 03:22

For you purpose, you may want to use tileLoadFunction (API doc) from ol.source.ImageWMS

To illustrate, you can look below. The 2 "secrets" are customLoader and for authentication to uncomment req.setRequestHeader("Authorization", "Basic " + window.btoa(user + ":" + pass));

<!DOCTYPE html>
<html>
  <head>
    <title>Tiled WMS</title>
    <link rel="stylesheet" href="https://openlayers.org/en/v4.6.5/css/ol.css" type="text/css">
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <script src="https://openlayers.org/en/v4.6.5/build/ol.js"></script>
  </head>
  <body>
    <div id="map" class="map"></div>
    <script>
      function customLoader(tile, src) {
        var client = new XMLHttpRequest();
        client.open('GET', src);
        // Uncomment to pass authentication header
        //req.setRequestHeader("Authorization", "Basic " + window.btoa(user + ":" + pass));
        client.onload = function() {
          tile.getImage().src = src;
        };
        client.send();
      }
      var layers = [
        new ol.layer.Tile({
          source: new ol.source.OSM()
        }),
        new ol.layer.Tile({
          extent: [-13884991, 2870341, -7455066, 6338219],
          source: new ol.source.TileWMS({
            url: 'https://ahocevar.com/geoserver/wms',
            tileLoadFunction: customLoader,
            params: {'LAYERS': 'topp:states', 'TILED': true},
            serverType: 'geoserver',
            // Countries have transparency, so do not fade tiles:
            transition: 0
          })
        })
      ];
      var map = new ol.Map({
        layers: layers,
        target: 'map',
        view: new ol.View({
          center: [-10997148, 4569099],
          zoom: 4
        })
      });
    </script>
  </body>
</html>

The answer is mainly borrowed from How to add a http header to openlayers3 requests? but with some adaptations as the syntax provided was not working.

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