Sharing of local file upload technology of SAP ui5 fileuploader

When we use SAP UI5 Of FileUploader Control , When uploading local files , The entry of its execution logic , Namely FileUploader.prototype.upload：

First, determine whether the control has been disable：

if (!this.getEnabled()) {
    
			return;
		}

SAP UI5 FileUploader The bottom layer can be based on form Of multipart/form-data perhaps XHR There are two technical ways to upload files , This can be seen clearly in the following source code .

use first getDomRef obtain fu_form, That is, the highlighted area in the figure below ：

try {
    
			this._bUploading = true;
			if (this.getSendXHR() && window.File) {
    
				var aFiles = this.FUEl.files;
				if (bPreProcessFiles) {
    
					this._sendProcessedFilesWithXHR(aFiles);
				} else {
    
					this._sendFilesWithXHR(aFiles);
				}
			} else if (uploadForm) {
    
				// In order to do the submit, the action DOM attribute of the inner form should be accurate.
				// If there is a change in the passed to the uploadUrl property string, we must ensure that it is
				// applied in the DOM and the submit is performed after there is new rendering.
				sActionAttr = uploadForm.getAttribute("action");
				if (sActionAttr !== this.getUploadUrl()) {
    
					this._submitAfterRendering = true;
				} else {
    
					this._submitAndResetValue();
				}
			}

If the returned object instance is not empty , Instruction use form To submit local code .

Now you are ready to submit the document ：_submitAndResetValue

It's called HTML form Native submit Method to submit ：

The server returned a File uploaded ok! String ：

This string is hidden iframe You can see it in the library ：

I can't visit this.oIFrameRef.contentWindow.document.body.innerHTML;：

Error message ：VM1992:1 Uncaught DOMException: Blocked a frame with origin “http://localhost:8080” from accessing a cross-origin frame.

Out of commission JavaScript Visit... From different sources iframe, To avoid any possible safety risks . For homologous strategies , The browser will prevent the script from trying to access iframe.

actually , I can't be 8080 Port of index.html In context , View another iframe Any attribute of , Report the same mistake ：

Then I'll be in advance iframe Detect on creation ：

Just created iframe,href yes about:blank:

Until this function is executed ,this.oIFrameRef.contentWindow.location.href Are accessible ：

beforeRendering In the hook of ,this.oIFrameRef.contentWindow.location.href Still available , however afterRendering Your hook won't work ：

This before and afterRendering The hook , Click on Browse… Button to select a local file , It will be triggered once each .

After selection , Click on Upload Button , It will trigger again ：

Click on upload File after , perform submit Before , All can be accessed normally ：this.oIFrameRef.contentWindow.location.href

post To 3003 after , No more visits ：