Img src path with header params to pass

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攒了一身酷
攒了一身酷 2020-12-03 02:07

I have an img tag in jsp page where the src path requires header parameters to pass to get the image. How can we achieve it?

4条回答
  •  遥遥无期
    2020-12-03 02:27

    First, you'll need to make an ajax request that sets the headers. Then, you need to use some HTML5 APIs to convert binary data recieved to base64. Finally, set the image src with the data: protocol and your base64 data.

    var oReq = new XMLHttpRequest();
    oReq.open("GET", "yourpage.jsp", true);
    oReq.setRequestHeader("Your-Header-Here", "Value");
    // use multiple setRequestHeader calls to set multiple values
    oReq.responseType = "arraybuffer";
    oReq.onload = function (oEvent) {
      var arrayBuffer = oReq.response; // Note: not oReq.responseText
      if (arrayBuffer) {
        var u8 = new Uint8Array(arrayBuffer);
        var b64encoded = btoa(String.fromCharCode.apply(null, u8));
        var mimetype="image/png"; // or whatever your image mime type is
        document.getElementById("yourimageidhere").src="data:"+mimetype+";base64,"+b64encoded;
      }
    };
    oReq.send(null);
    

    Sources:

    https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Sending_and_Receiving_Binary_Data

    How to convert uint8 Array to base64 Encoded String?

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