Repository navigation
Expand file tree
/
Copy pathindex.md
More file actions
138 lines (97 loc) · 4.32 KB
/
Copy pathindex.md
File metadata and controls
138 lines (97 loc) · 4.32 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
---
title: DirectoryReaderSync
slug: Web/API/DirectoryReaderSync
page-type: web-api-interface
status:
- deprecated
- non-standard
browser-compat: api.DirectoryReaderSync
---
{{APIRef("File and Directory Entries API")}}{{Non-standard_Header}}
The `DirectoryReaderSync` interface lets you read the entries in a directory.
> [!WARNING]
> This interface is deprecated and is no more on the standard track.
> _Do not use it anymore._ Use the [File and Directory Entries API](/en-US/docs/Web/API/File_and_Directory_Entries_API) instead.
## Basic concepts
Before you call the only method in this interface, [`readEntries()`](#readentries), create the [`DirectoryEntrySync`](/en-US/docs/Web/API/DirectoryEntrySync) object. But DirectoryEntrySync (as well as [`FileEntrySync`](/en-US/docs/Web/API/FileEntrySync)) is not a data type that you can pass between a calling app and Web Worker thread. It's not a big deal, because you don't really need to have the main app and the worker thread see the same JavaScript object; you just need them to access the same files. You can do that by passing a list of `filesystem:` URLs—which are just strings—instead of a list of entries. You can also use the `filesystem:` URL to look up the entry with `resolveLocalFileSystemURL()`. That gets you back to a DirectoryEntrySync (as well as FileEntrySync) object.
### Example
In the following code snippet from [HTML5Rocks (web.dev)](https://web.dev/articles/filesystem-sync), we create Web Workers and pass data from it to the main app.
```js
// Taking care of the browser-specific prefixes.
window.resolveLocalFileSystemURL =
window.resolveLocalFileSystemURL || window.webkitResolveLocalFileSystemURL;
// Create web workers
const worker = new Worker("worker.js");
worker.onmessage = (e) => {
const urls = e.data.entries;
urls.forEach((url) => {
window.resolveLocalFileSystemURL(url, (fileEntry) => {
// Print out file's name.
console.log(fileEntry.name);
});
});
};
worker.postMessage({ cmd: "list" });
```
The following is `worker.js` code that gets the contents of the directory.
```js
// worker.js
// Taking care of the browser-specific prefixes.
self.requestFileSystemSync =
self.webkitRequestFileSystemSync || self.requestFileSystemSync;
// Global for holding the list of entry file system URLs.
const paths = [];
function getAllEntries(dirReader) {
const entries = dirReader.readEntries();
for (const entry of entries) {
// Stash this entry's filesystem in URL
paths.push(entry.toURL());
// If this is a directory, traverse.
if (entry.isDirectory) {
getAllEntries(entry.createReader());
}
}
}
// Forward the error to main app.
function onError(e) {
postMessage(`ERROR: ${e.toString()}`);
}
self.onmessage = (e) => {
const cmd = e.data.cmd;
// Ignore everything else except our 'list' command.
if (!cmd || cmd !== "list") {
return;
}
try {
const fs = requestFileSystemSync(TEMPORARY, 1024 * 1024 /* 1MB */);
getAllEntries(fs.root.createReader());
self.postMessage({ entries: paths });
} catch (e) {
onError(e);
}
};
```
## Method
### readEntries()
Returns a list of entries from a specific directory. Call this method until an empty array is returned.
#### Syntax
```js-nolint
readEntries()
```
##### Parameters
None.
##### Return value
Array containing [`FileEntrySync`](/en-US/docs/Web/API/FileEntrySync) and [`DirectoryEntrySync`](/en-US/docs/Web/API/DirectoryEntrySync).
##### Exceptions
This method can raise a [DOMException](/en-US/docs/Web/API/DOMException) with the following codes:
| Exception | Description |
| ------------------- | ---------------------------------------------------------------------------------- |
| `NOT_FOUND_ERR` | The directory does not exist. |
| `INVALID_STATE_ERR` | The directory has been modified since the first call to readEntries was processed. |
| `SECURITY_ERR` | The browser determined that it was not safe to look up the metadata. |
## Specifications
This feature is not part of any specification anymore. It is no longer on track to become a standard.
## Browser compatibility
{{Compat}}
## See also
- [File and Directory Entries API](/en-US/docs/Web/API/File_and_Directory_Entries_API)