You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
318 lines
7.9 KiB
Markdown
318 lines
7.9 KiB
Markdown
# qs
|
|
|
|
A querystring parsing and stringifying library with some added security.
|
|
|
|
[](http://travis-ci.org/hapijs/qs)
|
|
|
|
Lead Maintainer: [Nathan LaFreniere](https://github.com/nlf)
|
|
|
|
The **qs** module was originally created and maintained by [TJ Holowaychuk](https://github.com/visionmedia/node-querystring).
|
|
|
|
## Usage
|
|
|
|
```javascript
|
|
var Qs = require('qs');
|
|
|
|
var obj = Qs.parse('a=c'); // { a: 'c' }
|
|
var str = Qs.stringify(obj); // 'a=c'
|
|
```
|
|
|
|
### Parsing Objects
|
|
|
|
```javascript
|
|
Qs.parse(string, [options]);
|
|
```
|
|
|
|
**qs** allows you to create nested objects within your query strings, by surrounding the name of sub-keys with square brackets `[]`, or prefixing the sub-key with a dot `.`.
|
|
For example, the string `'foo[bar]=baz'` converts to:
|
|
|
|
```javascript
|
|
{
|
|
foo: {
|
|
bar: 'baz'
|
|
}
|
|
}
|
|
```
|
|
|
|
When using the `plainObjects` option the parsed value is returned as a plain object, created via `Object.create(null)` and as such you should be aware that prototype methods will not exist on it and a user may set those names to whatever value they like:
|
|
|
|
```javascript
|
|
Qs.parse('a.hasOwnProperty=b', { plainObjects: true });
|
|
// { a: { hasOwnProperty: 'b' } }
|
|
```
|
|
|
|
By default parameters that would overwrite properties on the object prototype are ignored, if you wish to keep the data from those fields either use `plainObjects` as mentioned above, or set `allowPrototypes` to `true` which will allow user input to overwrite those properties. *WARNING* It is generally a bad idea to enable this option as it can cause problems when attempting to use the properties that have been overwritten. Always be careful with this option.
|
|
|
|
```javascript
|
|
Qs.parse('a.hasOwnProperty=b', { allowPrototypes: true });
|
|
// { a: { hasOwnProperty: 'b' } }
|
|
```
|
|
|
|
URI encoded strings work too:
|
|
|
|
```javascript
|
|
Qs.parse('a%5Bb%5D=c');
|
|
// { a: { b: 'c' } }
|
|
```
|
|
|
|
You can also nest your objects, like `'foo[bar][baz]=foobarbaz'`:
|
|
|
|
```javascript
|
|
{
|
|
foo: {
|
|
bar: {
|
|
baz: 'foobarbaz'
|
|
}
|
|
}
|
|
}
|
|
```
|
|
|
|
By default, when nesting objects **qs** will only parse up to 5 children deep. This means if you attempt to parse a string like
|
|
`'a[b][c][d][e][f][g][h][i]=j'` your resulting object will be:
|
|
|
|
```javascript
|
|
{
|
|
a: {
|
|
b: {
|
|
c: {
|
|
d: {
|
|
e: {
|
|
f: {
|
|
'[g][h][i]': 'j'
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
```
|
|
|
|
This depth can be overridden by passing a `depth` option to `Qs.parse(string, [options])`:
|
|
|
|
```javascript
|
|
Qs.parse('a[b][c][d][e][f][g][h][i]=j', { depth: 1 });
|
|
// { a: { b: { '[c][d][e][f][g][h][i]': 'j' } } }
|
|
```
|
|
|
|
The depth limit helps mitigate abuse when **qs** is used to parse user input, and it is recommended to keep it a reasonably small number.
|
|
|
|
For similar reasons, by default **qs** will only parse up to 1000 parameters. This can be overridden by passing a `parameterLimit` option:
|
|
|
|
```javascript
|
|
Qs.parse('a=b&c=d', { parameterLimit: 1 });
|
|
// { a: 'b' }
|
|
```
|
|
|
|
An optional delimiter can also be passed:
|
|
|
|
```javascript
|
|
Qs.parse('a=b;c=d', { delimiter: ';' });
|
|
// { a: 'b', c: 'd' }
|
|
```
|
|
|
|
Delimiters can be a regular expression too:
|
|
|
|
```javascript
|
|
Qs.parse('a=b;c=d,e=f', { delimiter: /[;,]/ });
|
|
// { a: 'b', c: 'd', e: 'f' }
|
|
```
|
|
|
|
Option `allowDots` can be used to disable dot notation:
|
|
|
|
```javascript
|
|
Qs.parse('a.b=c', { allowDots: false });
|
|
// { 'a.b': 'c' } }
|
|
```
|
|
|
|
### Parsing Arrays
|
|
|
|
**qs** can also parse arrays using a similar `[]` notation:
|
|
|
|
```javascript
|
|
Qs.parse('a[]=b&a[]=c');
|
|
// { a: ['b', 'c'] }
|
|
```
|
|
|
|
You may specify an index as well:
|
|
|
|
```javascript
|
|
Qs.parse('a[1]=c&a[0]=b');
|
|
// { a: ['b', 'c'] }
|
|
```
|
|
|
|
Note that the only difference between an index in an array and a key in an object is that the value between the brackets must be a number
|
|
to create an array. When creating arrays with specific indices, **qs** will compact a sparse array to only the existing values preserving
|
|
their order:
|
|
|
|
```javascript
|
|
Qs.parse('a[1]=b&a[15]=c');
|
|
// { a: ['b', 'c'] }
|
|
```
|
|
|
|
Note that an empty string is also a value, and will be preserved:
|
|
|
|
```javascript
|
|
Qs.parse('a[]=&a[]=b');
|
|
// { a: ['', 'b'] }
|
|
Qs.parse('a[0]=b&a[1]=&a[2]=c');
|
|
// { a: ['b', '', 'c'] }
|
|
```
|
|
|
|
**qs** will also limit specifying indices in an array to a maximum index of `20`. Any array members with an index of greater than `20` will
|
|
instead be converted to an object with the index as the key:
|
|
|
|
```javascript
|
|
Qs.parse('a[100]=b');
|
|
// { a: { '100': 'b' } }
|
|
```
|
|
|
|
This limit can be overridden by passing an `arrayLimit` option:
|
|
|
|
```javascript
|
|
Qs.parse('a[1]=b', { arrayLimit: 0 });
|
|
// { a: { '1': 'b' } }
|
|
```
|
|
|
|
To disable array parsing entirely, set `parseArrays` to `false`.
|
|
|
|
```javascript
|
|
Qs.parse('a[]=b', { parseArrays: false });
|
|
// { a: { '0': 'b' } }
|
|
```
|
|
|
|
If you mix notations, **qs** will merge the two items into an object:
|
|
|
|
```javascript
|
|
Qs.parse('a[0]=b&a[b]=c');
|
|
// { a: { '0': 'b', b: 'c' } }
|
|
```
|
|
|
|
You can also create arrays of objects:
|
|
|
|
```javascript
|
|
Qs.parse('a[][b]=c');
|
|
// { a: [{ b: 'c' }] }
|
|
```
|
|
|
|
### Stringifying
|
|
|
|
```javascript
|
|
Qs.stringify(object, [options]);
|
|
```
|
|
|
|
When stringifying, **qs** always URI encodes output. Objects are stringified as you would expect:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: 'b' });
|
|
// 'a=b'
|
|
Qs.stringify({ a: { b: 'c' } });
|
|
// 'a%5Bb%5D=c'
|
|
```
|
|
|
|
Examples beyond this point will be shown as though the output is not URI encoded for clarity. Please note that the return values in these cases *will* be URI encoded during real usage.
|
|
|
|
When arrays are stringified, by default they are given explicit indices:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: ['b', 'c', 'd'] });
|
|
// 'a[0]=b&a[1]=c&a[2]=d'
|
|
```
|
|
|
|
You may override this by setting the `indices` option to `false`:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: ['b', 'c', 'd'] }, { indices: false });
|
|
// 'a=b&a=c&a=d'
|
|
```
|
|
|
|
You may use the `arrayFormat` option to specify the format of the output array
|
|
|
|
```javascript
|
|
Qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'indices' })
|
|
// 'a[0]=b&a[1]=c'
|
|
Qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'brackets' })
|
|
// 'a[]=b&a[]=c'
|
|
Qs.stringify({ a: ['b', 'c'] }, { arrayFormat: 'repeat' })
|
|
// 'a=b&a=c'
|
|
```
|
|
|
|
Empty strings and null values will omit the value, but the equals sign (=) remains in place:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: '' });
|
|
// 'a='
|
|
```
|
|
|
|
Properties that are set to `undefined` will be omitted entirely:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: null, b: undefined });
|
|
// 'a='
|
|
```
|
|
|
|
The delimiter may be overridden with stringify as well:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: 'b', c: 'd' }, { delimiter: ';' });
|
|
// 'a=b;c=d'
|
|
```
|
|
|
|
Finally, you can use the `filter` option to restrict which keys will be included in the stringified output.
|
|
If you pass a function, it will be called for each key to obtain the replacement value. Otherwise, if you
|
|
pass an array, it will be used to select properties and array indices for stringification:
|
|
|
|
```javascript
|
|
function filterFunc(prefix, value) {
|
|
if (prefix == 'b') {
|
|
// Return an `undefined` value to omit a property.
|
|
return;
|
|
}
|
|
if (prefix == 'e[f]') {
|
|
return value.getTime();
|
|
}
|
|
if (prefix == 'e[g][0]') {
|
|
return value * 2;
|
|
}
|
|
return value;
|
|
}
|
|
Qs.stringify({ a: 'b', c: 'd', e: { f: new Date(123), g: [2] } }, { filter: filterFunc })
|
|
// 'a=b&c=d&e[f]=123&e[g][0]=4'
|
|
Qs.stringify({ a: 'b', c: 'd', e: 'f' }, { filter: ['a', 'e'] })
|
|
// 'a=b&e=f'
|
|
Qs.stringify({ a: ['b', 'c', 'd'], e: 'f' }, { filter: ['a', 0, 2] })
|
|
// 'a[0]=b&a[2]=d'
|
|
```
|
|
|
|
### Handling of `null` values
|
|
|
|
By default, `null` values are treated like empty strings:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: null, b: '' });
|
|
// 'a=&b='
|
|
```
|
|
|
|
Parsing does not distinguish between parameters with and without equal signs. Both are converted to empty strings.
|
|
|
|
```javascript
|
|
Qs.parse('a&b=')
|
|
// { a: '', b: '' }
|
|
```
|
|
|
|
To distinguish between `null` values and empty strings use the `strictNullHandling` flag. In the result string the `null`
|
|
values have no `=` sign:
|
|
|
|
```javascript
|
|
Qs.stringify({ a: null, b: '' }, { strictNullHandling: true });
|
|
// 'a&b='
|
|
```
|
|
|
|
To parse values without `=` back to `null` use the `strictNullHandling` flag:
|
|
|
|
```javascript
|
|
Qs.parse('a&b=', { strictNullHandling: true });
|
|
// { a: null, b: '' }
|
|
|
|
```
|