docs » hs.http

Perform HTTP requests

API Overview

API Documentation

Variables

htmlEntities
Signature hs.http.htmlEntities[]
Type Variable
Description

A collection of common HTML Entities (&whatever;) and their UTF8 equivalents. To retrieve the UTF8 sequence for a given entity, reference the table as hs.http.htmlEntities["&key;"] where key is the text of the entity's name or a numeric reference like #number.

Notes:

  • This list is likely not complete. It is based on the list of common entities described at http://www.freeformatter.com/html-entities.html.
  • Additional entities can be temporarily added via the hs.http.registerEntity(...) function. If you feel you have a more official list of entities which contains items which are currently not included by default, please open up an issue at https://github.com/Hammerspoon/hammerspoon and your link will be considered.

  • To see a list of the currently defined entities, a __tostring meta-method is included so that referencing the table directly as a string will return the current definitions.

    • For reference, this meta-method is essentially the following:

      for i,v in hs.fnutils.sortByKeys(hs.http.htmlEntities) do print(string.format("%-10s %-10s %s\n", i, "&#"..tostring(hs.utf8.codepoint(v))..";", v)) end

    • Note that this list will not include the numeric conversion of entities (e.g. A), as this is handled by an __index metamethod to allow for all possible numeric values.

Functions

asyncGet
Signature hs.http.asyncGet(url, headers, callback)
Type Function
Description

Sends an HTTP GET request asynchronously

Parameters:

  • url - A string containing the URL to retrieve
  • headers - A table containing string keys and values representing the request headers, or nil to add no headers
  • callback - A function to be called when the request succeeds or fails. The function will be passed three parameters:
    • A number containing the HTTP response status
    • A string containing the response body
    • A table containing the response headers

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.

  • If the request fails, the callback function's first parameter will be negative and the second parameter will contain an error message. The third parameter will be nil
asyncPost
Signature hs.http.asyncPost(url, data, headers, callback)
Type Function
Description

Sends an HTTP POST request asynchronously

Parameters:

  • url - A string containing the URL to submit to
  • data - A string containing the request body, or nil to send no body
  • headers - A table containing string keys and values representing the request headers, or nil to add no headers
  • callback - A function to be called when the request succeeds or fails. The function will be passed three parameters:
    • A number containing the HTTP response status
    • A string containing the response body
    • A table containing the response headers

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.

  • If the request fails, the callback function's first parameter will be negative and the second parameter will contain an error message. The third parameter will be nil
convertHtmlEntities
Signature hs.http.convertHtmlEntities(inString) -> outString
Type Function
Description

Convert all recognized HTML Entities in the inString to appropriate UTF8 byte sequences and returns the converted text.

Parameters:

  • inString -- A string containing any number of HTML Entities (&whatever;) in the text.

Returns:

  • outString -- the input string with all recognized HTML Entity sequences converted to UTF8 byte sequences.

Notes:

  • Recognized HTML Entities are those registered in hs.http.htmlEntities or numeric entity sequences: &#n; where n can be any integer number.
  • This function is especially useful as a post-filter to data retrieved by the hs.http.get and hs.http.asyncGet functions.
doAsyncRequest
Signature hs.http.doAsyncRequest(url, method, data, headers, callback)
Type Function
Description

Creates an HTTP request and executes it asynchronously

Parameters:

  • url - A string containing the URL
  • method - A string containing the HTTP method to use (e.g. "GET", "POST", etc)
  • data - A string containing the request body, or nil to send no body
  • headers - A table containing string keys and values representing request header keys and values, or nil to add no headers
  • callback - A function to called when the response is received. The function should accept three arguments:
    • code - A number containing the HTTP response code
    • body - A string containing the body of the response
    • headers - A table containing the HTTP headers of the response

Returns:

  • None

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.
  • If the Content-Type response header begins text/ then the response body return value is a UTF8 string. Any other content type passes the response body, unaltered, as a stream of bytes.
doRequest
Signature hs.http.doRequest(url, method, [data, headers]) -> int, string, table
Type Function
Description

Creates an HTTP request and executes it synchronously

Parameters:

  • url - A string containing the URL
  • method - A string containing the HTTP method to use (e.g. "GET", "POST", etc)
  • data - An optional string containing the data to POST to the URL, or nil to send no data
  • headers - An optional table of string keys and values used as headers for the request, or nil to add no headers

Returns:

  • A number containing the HTTP response status code
  • A string containing the response body
  • A table containing the response headers

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.

  • This function is synchronous and will therefore block all Lua execution until it completes. You are encouraged to use the asynchronous functions.

  • If you attempt to connect to a local Hammerspoon server created with hs.httpserver, then Hammerspoon will block until the connection times out (60 seconds), return a failed result due to the timeout, and then the hs.httpserver callback function will be invoked (so any side effects of the function will occur, but it's results will be lost). Use hs.http.doAsyncRequest to avoid this.
  • If the Content-Type response header begins text/ then the response body return value is a UTF8 string. Any other content type passes the response body, unaltered, as a stream of bytes.
encodeForQuery
Signature hs.http.encodeForQuery(string) -> string
Type Function
Description

Returns a copy of the provided string in which characters that are not valid within an HTTP query key or value are escaped with their %## equivalent.

Parameters:

  • originalString - the string to make safe as a key or value for a query

Returns:

  • the converted string

Notes:

  • The intent of this function is to provide a valid key or a valid value for a query string, not to validate the entire query string. For this reason, ?, =, +, and & are included in the converted characters.
get
Signature hs.http.get(url, headers) -> int, string, table
Type Function
Description

Sends an HTTP GET request to a URL

Parameters

  • url - A string containing the URL to retrieve
  • headers - A table containing string keys and values representing the request headers, or nil to add no headers

Returns:

  • A number containing the HTTP response status
  • A string containing the response body
  • A table containing the response headers

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.

  • This function is synchronous and will therefore block all other Lua execution while the request is in progress, you are encouraged to use the asynchronous functions

  • If you attempt to connect to a local Hammerspoon server created with hs.httpserver, then Hammerspoon will block until the connection times out (60 seconds), return a failed result due to the timeout, and then the hs.httpserver callback function will be invoked (so any side effects of the function will occur, but it's results will be lost). Use hs.http.asyncGet to avoid this.
post
Signature hs.http.post(url, data, headers) -> int, string, table
Type Function
Description

Sends an HTTP POST request to a URL

Parameters

  • url - A string containing the URL to submit to
  • data - A string containing the request body, or nil to send no body
  • headers - A table containing string keys and values representing the request headers, or nil to add no headers

Returns:

  • A number containing the HTTP response status
  • A string containing the response body
  • A table containing the response headers

Notes:

  • If authentication is required in order to download the request, the required credentials must be specified as part of the URL (e.g. "http://user:password@host.com/"). If authentication fails, or credentials are missing, the connection will attempt to continue without credentials.

  • This function is synchronous and will therefore block all other Lua execution while the request is in progress, you are encouraged to use the asynchronous functions

  • If you attempt to connect to a local Hammerspoon server created with hs.httpserver, then Hammerspoon will block until the connection times out (60 seconds), return a failed result due to the timeout, and then the hs.httpserver callback function will be invoked (so any side effects of the function will occur, but it's results will be lost). Use hs.http.asyncPost to avoid this.
registerEntity
Signature hs.http.registerEntity(entity, codepoint) -> string
Type Function
Description

Registers an HTML Entity with the specified Unicode codepoint which can later referenced in your code as hs.http.htmlEntity[entity] for convenience and readability.

Parameters:

  • entity -- The full text of the HTML Entity as it appears in HTML encoded documents. A proper entity starts with & and ends with ; and entity labels which do not meet this will have them added -- future dereferences to get the corresponding UTF8 must include this initiator and terminator or they will not be recognized.
  • codepoint -- a Unicode codepoint in numeric or U+xxxx format to register with as the given entity.

Returns:

  • Returns the UTF8 byte sequence for the entity registered.

Notes:

  • If an entity label was previously registered, this will overwrite the previous value with a new one.
  • The return value is merely syntactic sugar and you do not need to save it locally; it can be safely ignored -- future access to the pre-converted entity should be retrieved as hs.http.htmlEntities[entity] in your code. It looks good when invoked from the console, though ☺.
urlParts
Signature hs.http.urlParts(url) -> table
Type Function
Description

Returns a table of keys containing the individual components of the provided url.

Parameters:

  • url - the url to parse into it's individual components

Returns:

  • a table containing any of the following keys which apply to the specified url:
    • absoluteString - The URL string for the URL as an absolute URL.
    • absoluteURL - An absolute URL that refers to the same resource as the provided URL.
    • baseURL - the base URL, if the URL is relative
    • fileSystemRepresentation - the URL’s unescaped path specified as a file system path
    • fragment - the fragment, if specified in the URL
    • host - the host for the URL
    • isFileURL - a boolean value indicating whether or not the URL represents a local file
    • lastPathComponent - the last path component specified in the URL
    • parameterString - the parameter string, if specified in the URL
    • password - the password, if specified in the URL
    • path - the unescaped path specified in the URL
    • pathComponents - an array containing the path components of the URL
    • pathExtension - the file extension, if specified in the URL
    • port - the port, if specified in the URL
    • query - the query, if specified in the URL
    • queryItems - if the URL contains a query string, then this field contains an array of the unescaped key-value pairs for each item. Each key-value pair is represented as a table in the array to preserve order. See notes for more information.
    • relativePath - the relative path of the URL without resolving against its base URL. If the path has a trailing slash it is stripped. If the URL is already an absolute URL, this contains the same value as path.
    • relativeString - a string representation of the relative portion of the URL. If the URL is already an absolute URL this contains the same value as absoluteString.
    • resourceSpecifier - the resource specified in the URL
    • scheme - the scheme of the URL
    • standardizedURL - the URL with any instances of ".." or "." removed from its path
    • user - the username, if specified in the URL

Notes:

  • This function assumes that the URL conforms to RFC 1808. If the URL is malformed or does not conform to RFC1808, then many of these fields may be missing.

  • A contrived example for the url http://user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment:

    hs.inspect(hs.http.urlParts("http://user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment")) { absoluteString = "http://user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment", absoluteURL = "http://user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment", fileSystemRepresentation = "/path/to a/../file.txt", fragment = "fragment", host = "host.site.com", isFileURL = false, lastPathComponent = "file.txt", parameterString = "parameter", password = "password", path = "/path/to a/../file.txt", pathComponents = { "/", "path", "to a", "..", "file.txt" }, pathExtension = "txt", port = 80, query = "query1=1&query2=a%28", queryItems = { { query1 = "1" }, { query2 = "a(" } }, relativePath = "/path/to a/../file.txt", relativeString = "http://user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment", resourceSpecifier = "//user:password@host.site.com:80/path/to%20a/../file.txt;parameter?query1=1&query2=a%28#fragment", scheme = "http", standardizedURL = "http://user:password@host.site.com:80/path/file.txt;parameter?query1=1&query2=a%28#fragment", user = "user" }

  • Because it is valid for a query key-value pair to be missing either the key or the value or both, the following conventions are used:

    • a missing key (e.g. '=value') will be represented as { "" = value }
    • a missing value (e.g. 'key=') will be represented as { key = "" }
    • a missing value with no = (e.g. 'key') will be represented as { key }
    • a missing key and value (e.g. '=') will be represente as { "" = "" }
    • an empty query item (e.g. a query ending in '&' or a query containing && between two other query items) will be represented as { "" }

  • At present Hammerspoon does not provide a way to represent a URL as a true Objective-C object within the OS X API. This affects the following keys:

    • relative URLs are not possible to express properly so baseURL will always be nil and relativePath and relativeString will always match path and absoluteString.
    • These limitations may change in a future update if the need for a more fully compliant URL treatment is determined to be necessary.