FilePicker: How to read file content

[mgordic]

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Category

[ ] Enhancement

[ ] Bug

[x] Question

Version

Please specify what version of the library you are using: [ Latest ]

Expected / Desired Behavior / Question

How can I read file content on save, as array buffer or base64 encoded string?

downloadFileContent does not return anything of those.

Thank you

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[AJIXuMuK]

Hi @mgordic,

If you're not in IE or Edge, you can use Blob API to get ArrayBuffer or Stream (File implements Blob interface).

Documentation: https://developer.mozilla.org/en-US/docs/Web/API/File

[mgordic]

Hi,

Thank you for your reply.

I need to support IE/Edge as well.

Do you maybe have some code example?

[AJIXuMuK]

@hugoabernier do you have any examples of that? I believe, this one was created by you (correct me if I wrong).

[hugoabernier]

@AJIXuMuK as much as I'd like to take the credit for this control, it is based on a code sample I submitted to the WebParts samples repo. It appears that the code for this control is derived from one of my code sample in the https://github.com/SharePoint/sp-dev-fx-webparts repo. (I'd love to know who submitted the PR so that I can thank them directly though!)

If you're using IE or Edge, you should have access to msSaveOrOpenBlob. It will be undefined if not in Edge or IE.

[AJIXuMuK]

@hugoabernier it was Piotr Siatka @siata13

[siata13]

Hey,
The implementation used File constructor which seems to be not supported in IE11.
I have created a bugfix and PR which should solve the issue.

Now, the downloadFileContent method should return a promise with a File object in IE also. After that, you can simply use FileReader, e.g.:

const fileResultContent = await filePickerResult.downloadFileContent();
const reader = new FileReader();
reader.readAsDataURL(fileResultContent);
reader.onload = async () => {
 // TODO: Implement your logic here.
};

[AJIXuMuK]

The PR has been merged and will be available in the next build. Or you can test it in current beta version.

[hugoabernier]

Thanks @siata13 for doing this!