I have the following two files:
index.html
<html>
<head>
<meta charset="utf-8" />
<title>Web Page</title>
<style type="text/css">
.text {
display: inline-block;
font-family: tahoma;
font-size: 14px;
max-width: 400px;
background-color: #ddedff;
padding: 10px;
text-align: justify;
}
</style>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript">
$(function(){
get_data('info.txt');
});
function get_data(file) {
var request = new Request(file);
fetch(request).then(function(response) {
return response.text().then(function(text) {
$('.text').html(text);
});
});
}
</script>
</head>
<body>
<div class="text"></div>
</body>
<html>
info.txt
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
When I open on Mozilla Firefox
the file: README.html
through this local URI
:
file:///C:/testing/README.html
it works as expected, I mean, the text on file: info.txt
is displayed properly.
But when I open the same URI
on Google Chrome
I get a blank screen and the following error on the console:
README.html:26 Fetch API cannot load file:///C:/testing/README.md. URL scheme must be "http" or "https" for CORS request.
get_data @ README.html:26
README.html:26 Uncaught (in promise) TypeError: Failed to fetch
at get_data (README.html:26)
at HTMLDocument.<anonymous> (README.html:21)
at l (jquery.min.js:2)
at c (jquery.min.js:2)
Do you have what can I do so I can open local files on Google Chrome
as I can do on Mozilla Firefox
?
If I have to do some tweak on:
chrome://flags/
that's acceptable for me.
EDIT
I tried launching Google Chrome
from the command line with the flag: --allow-file-access-from-files
as recommended here but now I get the following error:
README.html:26 Fetch API cannot load file:///C:/testing/README.md. URL scheme "file" is not supported.
get_data @ README.html:26
README.html:26 Uncaught (in promise) TypeError: Failed to fetch
at get_data (README.html:26)
at HTMLDocument.<anonymous> (README.html:21)
at l (jquery.min.js:2)
at c (jquery.min.js:2)
Thanks!
Fetch is an API to request data through networks using Http request, and we could also use this to request local files!
JavaScript | fetch() Method. The fetch() method in JavaScript is used to request to the server and load the information on the webpages. The request can be of any APIs that return the data of the format JSON or XML. This method returns a promise.
The Fetch API allows you to asynchronously request for a resource. Use the fetch() method to return a promise that resolves into a Response object. To get the actual data, you call one of the methods of the Response object e.g., text() or json() . These methods resolve into the actual data.
The Fetch API provides an interface for fetching resources (including across the network). It will seem familiar to anyone who has used XMLHttpRequest , but the new API provides a more powerful and flexible feature set.
For chrome you still need --allow-file-access-from-files
(and I recommend installing a separate chrome and using it solely for these projects to stay secure), but just shim fetch()
for XMLHttpRequest
for file://
requests:
if (/^file:\/\/\//.test(location.href)) {
let path = './';
let orig = fetch;
window.fetch = (resource) => ((/^[^/:]*:/.test(resource)) ?
orig(resource) :
new Promise(function(resolve, reject) {
let request = new XMLHttpRequest();
let fail = (error) => {reject(error)};
['error', 'abort'].forEach((event) => { request.addEventListener(event, fail); });
let pull = (expected) => (new Promise((resolve, reject) => {
if (
request.responseType == expected ||
(expected == 'text' && !request.responseType)
)
resolve(request.response);
else
reject(request.responseType);
}));
request.addEventListener('load', () => (resolve({
arrayBuffer : () => (pull('arraybuffer')),
blob : () => (pull('blob')),
text : () => (pull('text')),
json : () => (pull('json'))
})));
request.open('GET', resource.replace(/^\//, path));
request.send();
})
);
}
This shim will;
if
statement),fetch()
for any url that doesn't specify protocol (and thus non-file://
requests), and/root/bob.html
) with ones relative to the current path (since that would dangerously evaluate to C:\
or equivalent)Set path
to something else if your index.html
isn't actually at the root for the project.
If you need support for init, or anything other than text()
, you'll need to add it.
Explicit file://
requests wont be fulfilled, that's on purpose, but if you really do know what you're doing, you'll know how to make this work for you, and if you don't you shouldn't.
The following is useful if you're going to be doing this for multiple files. Swap out './'
for document.currentScript.getAttribute('data-root')
. Now you can put that snippet into its own file, say filesystemHelper.js
, and call like so in the various files:
<script src="../filesystemHelper.js" data-root="../"></script>
Pretty snazzy.
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