diff --git a/README.md b/README.md index 6d5d44982c..d0af2fe00a 100644 --- a/README.md +++ b/README.md @@ -66,6 +66,7 @@ - [HTML Form Posting](#-html-form-posting-browser) - [🆕 Progress capturing](#-progress-capturing) - [🆕 Rate limiting](#-progress-capturing) + - [🆕 AxiosHeaders](#-axiosheaders) - [Semver](#semver) - [Promises](#promises) - [TypeScript](#typescript) @@ -1291,6 +1292,260 @@ const {data} = await axios.post(LOCAL_SERVER_URL, myBuffer, { }); ``` +## 🆕 AxiosHeaders + +Axios has its own `AxiosHeaders` class to manipulate headers using a Map-like API that guarantees caseless work. +Although HTTP is case-insensitive in headers, Axios will retain the case of the original header for stylistic reasons +and for a workaround when servers mistakenly consider the header's case. +The old approach of directly manipulating headers object is still available, but deprecated and not recommended for future usage. + +### Working with headers + +An AxiosHeaders object instance can contain different types of internal values. that control setting and merging logic. +The final headers object with string values is obtained by Axios by calling the `toJSON` method. + +> Note: By JSON here we mean an object consisting only of string values intended to be sent over the network. + +The header value can be one of the following types: +- `string` - normal string value that will be sent to the server +- `null` - skip header when rendering to JSON +- `false` - skip header when rendering to JSON, additionally indicates that `set` method must be called with `rewrite` option set to `true` + to overwrite this value (Axios uses this internally to allow users to opt out of installing certain headers like `User-Agent` or `Content-Type`) +- `undefined` - value is not set + +> Note: The header value is considered set if it is not equal to undefined. + +The headers object is always initialized inside interceptors and transformers: + +```ts + axios.interceptors.request.use((request: InternalAxiosRequestConfig) => { + request.headers.set('My-header', 'value'); + + request.headers.set({ + "My-set-header1": "my-set-value1", + "My-set-header2": "my-set-value2" + }); + + request.headers.set('User-Agent', false); // disable subsequent setting the header by Axios + + request.headers.setContentType('text/plain'); + + request.headers['My-set-header2'] = 'newValue' // direct access is deprecated + + return request; + } + ); +```` + +You can iterate over an `AxiosHeaders` instance using a `for...of` statement: + +````js +const headers = new AxiosHeaders({ + foo: '1', + bar: '2', + baz: '3' +}); + +for(const [header, value] of headers) { + console.log(header, value); +} + +// foo 1 +// bar 2 +// baz 3 +```` + +### new AxiosHeaders(headers?) + +Constructs a new `AxiosHeaders` instance. + +``` +constructor(headers?: RawAxiosHeaders | AxiosHeaders | string); +``` + +If the headers object is a string, it will be parsed as RAW HTTP headers. + +````js +const headers = new AxiosHeaders(` +Host: www.bing.com +User-Agent: curl/7.54.0 +Accept: */*`); + +console.log(headers); + +// Object [AxiosHeaders] { +// host: 'www.bing.com', +// 'user-agent': 'curl/7.54.0', +// accept: '*/*' +// } +```` + +### AxiosHeaders#set + +```ts +set(headerName, value: Axios, rewrite?: boolean); +set(headerName, value, rewrite?: (this: AxiosHeaders, value: string, name: string, headers: RawAxiosHeaders) => boolean); +set(headers?: RawAxiosHeaders | AxiosHeaders | string, rewrite?: boolean); +``` + +The `rewrite` argument controls the overwriting behavior: +- `false` - do not overwrite if header's value is set (is not `undefined`) +- `undefined` (default) - overwrite the header unless its value is set to `false` +- `true` - rewrite anyway + +The option can also accept a user-defined function that determines whether the value should be overwritten or not. + +Returns `this`. + +### AxiosHeaders#get(header) + +``` + get(headerName: string, matcher?: true | AxiosHeaderMatcher): AxiosHeaderValue; + get(headerName: string, parser: RegExp): RegExpExecArray | null; +```` + +Returns the internal value of the header. It can take an extra argument to parse the header's value with `RegExp.exec`, +matcher function or internal key-value parser. + +```ts +const headers = new AxiosHeaders({ + 'Content-Type': 'multipart/form-data; boundary=Asrf456BGe4h' +}); + +console.log(headers.get('Content-Type')); +// multipart/form-data; boundary=Asrf456BGe4h + +console.log(headers.get('Content-Type', true)); // parse key-value pairs from a string separated with \s,;= delimiters: +// [Object: null prototype] { +// 'multipart/form-data': undefined, +// boundary: 'Asrf456BGe4h' +// } + + +console.log(headers.get('Content-Type', (value, name, headers) => { + return String(value).replace(/a/g, 'ZZZ'); +})); +// multipZZZrt/form-dZZZtZZZ; boundZZZry=Asrf456BGe4h + +console.log(headers.get('Content-Type', /boundary=(\w+)/)?.[0]); +// boundary=Asrf456BGe4h + +``` + +Returns the value of the header. + +### AxiosHeaders#has(header, matcher?) + +``` +has(header: string, matcher?: AxiosHeaderMatcher): boolean; +``` + +Returns `true` if the header is set (has no `undefined` value). + +### AxiosHeaders#delete(header, matcher?) + +``` +delete(header: string | string[], matcher?: AxiosHeaderMatcher): boolean; +``` + +Returns `true` if at least one header has been removed. + +### AxiosHeaders#clear(matcher?) + +``` +clear(matcher?: AxiosHeaderMatcher): boolean; +``` + +Removes all headers. +Unlike the `delete` method matcher, this optional matcher will be used to match against the header name rather than the value. + +```ts +const headers = new AxiosHeaders({ + 'foo': '1', + 'x-foo': '2', + 'x-bar': '3', +}); + +console.log(headers.clear(/^x-/)); // true + +console.log(headers.toJSON()); // [Object: null prototype] { foo: '1' } +``` + +Returns `true` if at least one header has been cleared. + +### AxiosHeaders#normalize(format); + +If the headers object was changed directly, it can have duplicates with the same name but in different cases. +This method normalizes the headers object by combining duplicate keys into one. +Axios uses this method internally after calling each interceptor. +Set `format` to true for converting headers name to lowercase and capitalize the initial letters (`cOntEnt-type` => `Content-Type`) + +```js +const headers = new AxiosHeaders({ + 'foo': '1', +}); + +headers.Foo = '2'; +headers.FOO = '3'; + +console.log(headers.toJSON()); // [Object: null prototype] { foo: '1', Foo: '2', FOO: '3' } +console.log(headers.normalize().toJSON()); // [Object: null prototype] { foo: '3' } +console.log(headers.normalize(true).toJSON()); // [Object: null prototype] { Foo: '3' } +``` + +Returns `this`. + +### AxiosHeaders#concat(...targets) + +``` +concat(...targets: Array): AxiosHeaders; +``` + +Merges the instance with targets into a new `AxiosHeaders` instance. If the target is a string, it will be parsed as RAW HTTP headers. + +Returns a new `AxiosHeaders` instance. + +### AxiosHeaders#toJSON(asStrings?) + +```` +toJSON(asStrings?: boolean): RawAxiosHeaders; +```` + +Resolve all internal headers values into a new null prototype object. +Set `asStrings` to true to resolve arrays as a string containing all elements, separated by commas. + +### AxiosHeaders.from(thing?) + +```` +from(thing?: AxiosHeaders | RawAxiosHeaders | string): AxiosHeaders; +```` + +Returns a new `AxiosHeaders` instance created from the raw headers passed in, +or simply returns the given headers object if it's an `AxiosHeaders` instance. + +### AxiosHeaders.concat(...targets) + +```` +concat(...targets: Array): AxiosHeaders; +```` + +Returns a new `AxiosHeaders` instance created by merging the target objects. + +### Shortcuts + +The following shortcuts are available: + +- `setContentType`, `getContentType`, `hasContentType` + +- `setContentLength`, `getContentLength`, `hasContentLength` + +- `setAccept`, `getAccept`, `hasAccept` + +- `setUserAgent`, `getUserAgent`, `hasUserAgent` + +- `setContentEncoding`, `getContentEncoding`, `hasContentEncoding` + + ## Semver Until axios reaches a `1.0` release, breaking changes will be released with a new minor version. For example `0.5.1`, and `0.5.4` will have the same API, but `0.6.0` will have breaking changes.