Dexador

Dexador is yet another HTTP client for Common Lisp with neat APIs and connection-pooling.

Warning

This software is still BETA quality. The APIs will be likely to change.

Differences from Drakma

• Fast, particularly when requesting to the same host (See Benchmark)
• Neat APIs
• Signal a condition when HTTP request failed
• OpenSSL isn't required for Windows

See also a presentation given at Lisp Meetup #31.

Usage

(dex:get "http://lisp.org/")

(dex:post "https://example.com/login"
          :content '(("name" . "fukamachi") ("password" . "1ispa1ien")))

Posting a form-data

You can specify a form-data at :content in an association list. The data will be sent in application/x-www-form-urlencoded format.

(dex:post "http://example.com/entry/create"
          :content '(("title" . "The Truth About Lisp")
                     ("body" . "In which the truth about lisp is revealed, and some alternatives are enumerated.")))

Auto-detects Multipart

If the association list contains a pathname, the data will be sent as multipart/form-data.

(dex:post "http://example.com/entry/create"
          :content '(("photo" . #P"images/2015030201.jpg")))

Following redirects (GET or HEAD)

If the server reports that the requested page has moved to a different location (indicated with a Location header and a 3XX response code), Dexador will redo the request on the new place, the fourth return value shows.

(dex:head "http://lisp.org")
;=> ""
;   200
;   #<HASH-TABLE :TEST EQUAL :COUNT 7 {100D2A47A3}>
;   #<QURI.URI.HTTP:URI-HTTP http://lisp.org/index.html>
;   NIL

You can limit the count of redirection by specifying :max-redirects with an integer. The default value is 5.

Using cookies

Dexador adopts cl-cookie for its cookie management. All functions takes a cookie-jar instance at :cookie-jar.

(defvar *cookie-jar* (cl-cookie:make-cookie-jar))

(dex:head "https://mixi.jp" :cookie-jar *cookie-jar* :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Dexador/0.1 (SBCL 1.2.9); Darwin; 14.1.0
;   Host: mixi.jp
;   Accept: */*
;   
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
;   HTTP/1.1 200 OK
;   Date: Tue, 10 Mar 2015 10:16:29 GMT
;   Server: Apache
;   X-Dealer: 152151
;   X-XRDS-Location: https://mixi.jp/xrds.pl
;   Cache-Control: no-cache
;   Pragma: no-cache
;   Vary: User-Agent
;   Content-Type: text/html; charset=EUC-JP
;   Set-Cookie: _auid=9d47ca5a00ce4980c41511beb2626fd4; domain=.mixi.jp; path=/; expires=Thu, 09-Mar-2017 10:16:29 GMT
;   Set-Cookie: _lcp=8ee4121c9866435007fff2c90dc31a4d; domain=.mixi.jp; expires=Wed, 11-Mar-2015 10:16:29 GMT
;   X-Content-Type-Options: nosniff
;   
;   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

;; Again
(dex:head "https://mixi.jp" :cookie-jar *cookie-jar* :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Dexador/0.1 (SBCL 1.2.9); Darwin; 14.1.0
;   Host: mixi.jp
;   Accept: */*
;   Cookie: _auid=b878756ed71a0ed5bcf527e324c78f8c; _lcp=8ee4121c9866435007fff2c90dc31a4d
;   
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
;   HTTP/1.1 200 OK
;   Date: Tue, 10 Mar 2015 10:16:59 GMT
;   Server: Apache
;   X-Dealer: 152146
;   X-XRDS-Location: https://mixi.jp/xrds.pl
;   Cache-Control: no-cache
;   Pragma: no-cache
;   Vary: User-Agent
;   Content-Type: text/html; charset=EUC-JP
;   Set-Cookie: _auid=b878756ed71a0ed5bcf527e324c78f8c; domain=.mixi.jp; path=/; expires=Thu, 09-Mar-2017 10:16:59 GMT
;   Set-Cookie: _lcp=8ee4121c9866435007fff2c90dc31a4d; domain=.mixi.jp; expires=Wed, 11-Mar-2015 10:16:59 GMT
;   X-Content-Type-Options: nosniff
;   
;   <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Authorization

You can only supply either basic or bearer authorization.

Basic Authorization

(dex:head "http://www.hatena.ne.jp/" :basic-auth '("nitro_idiot" . "password") :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Dexador/0.1 (SBCL 1.2.9); Darwin; 14.1.0
;   Host: www.hatena.ne.jp
;   Accept: */*
;   Authorization: Basic bml0cm9faWRpb3Q6cGFzc3dvcmQ=
;
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bearer Authorization

(dex:head "http://www.hatena.ne.jp/" :bearer-auth "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9"
                                     :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Dexador/0.9.15 (SBCL 2.4.3); Linux; 6.7.0-20-amd64
;   Host: www.hatena.ne.jp
;   Accept: */*
;   Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9
;   
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Faking a User-Agent header

You can overwrite the default User-Agent header by simply specifying "User-Agent" in :headers.

(dex:head "http://www.sbcl.org/" :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Dexador/0.1 (SBCL 1.2.6); Darwin; 14.1.0
;   Host: www.sbcl.org
;   Accept: */*
;   
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

(dex:head "http://www.sbcl.org/"
          :headers '(("User-Agent" . "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/600.3.18 (KHTML, like Gecko) Version/8.0.3 Safari/600.3.18"))
          :verbose t)
;-> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
;   HEAD / HTTP/1.1
;   User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/600.3.18 (KHTML, like Gecko) Version/8.0.3 Safari/600.3.18
;   Host: www.sbcl.org
;   Accept: */*
;   
;   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Reusing a connection

Dexador reuses a connection by default. As it skips a TCP handshake, it would be much faster when you send requests to the same host continuously.

Handling unexpected HTTP status code

Dexador signals a condition http-request-failed when the server returned 4xx or 5xx status code.

;; Handles 400 bad request
(handler-case (dex:get "http://lisp.org")
  (dex:http-request-bad-request ()
    ;; Runs when 400 bad request returned
    )
  (dex:http-request-failed (e)
    ;; For other 4xx or 5xx
    (format *error-output* "The server returned ~D" (dex:response-status e))))

;; Ignore 404 Not Found and continue
(handler-bind ((dex:http-request-not-found #'dex:ignore-and-continue))
  (dex:get "http://lisp.org"))

;; Retry
(handler-bind ((dex:http-request-failed #'dex:retry-request))
  (dex:get "http://lisp.org"))

;; Retry 5 times
(let ((retry-request (dex:retry-request 5 :interval 3)))
  (handler-bind ((dex:http-request-failed retry-request))
    (dex:get "http://lisp.org")))

Proxy

You can connect via proxy.

(dex:get "http://lisp.org/" :proxy "http://proxy.yourcompany.com:8080/")

You can connect via SOCKS5 proxy.

(dex:get "https://www.facebookcorewwwi.onion/" :proxy "socks5://127.0.0.1:9150")

You can set the default proxy by setting dex:*default-proxy* which defaults to the value of the environment variable HTTPS_PROXY or HTTP_PROXY

Functions

All functions take similar arguments.

• uri (string or quri:uri)
• method (keyword)
  • The HTTP request method: :GET, :HEAD, :OPTIONS, :PUT, :POST, or :DELETE. The default is :GET.
• version (number)
  • The version of the HTTP protocol: typically 1.0 or 1.1. The default is 1.1.
• content (string, alist or pathname)
  • The body of the request. content may be an alist containing key value pairs, where the value can be a string, pathname, an (array (unsigned-byte 8) (*)), or a cons. If the value is a cons, then it may contain a :content-type override such as: :content `(("key" ,(make-array 5 :element-type '(unsigned-byte 8)) :content-type "application/octets")) which will result in a multipart form encoded submission.
• headers (alist)
  • The headers of the request. If the value of a pair is NIL, the header won't be sent. You can overwrite the default headers (Host, User-Agent, Accept, Content-Type) by this with the same header name.
• basic-auth (cons of username and password)
  • Username and password for basic authorization. This is a cons having username at car and password at cdr. (e.g. '("foo" . "bar"))
• cookie-jar (cookie-jar of cl-cookie)
  • A cookie jar object.
• connect-timeout (fixnum)
  • The seconds to timeout until the HTTP connection established. The default is 10, the value of *default-connect-timeout*.
• read-timeout (fixnum)
  • The seconds to timeout until the whole HTTP body read. The default is 10, the value of *default-read-timeout*.
• keep-alive (boolean)
  • A flag if the connection keep connected even after the HTTP request. The default is T.
• use-connection-pool (boolean)
  • When combined with :keep-alive t, will internally cache the socket connection to web servers to avoid having to open new ones. This is compatible with :want-stream t (when you close the returned stream or it is garbage collected the connection will be returned to the pool). If you pass in a stream with :stream then the connection pool is not used (unless there is a redirect to a new web server). This is not supported when using the WINHTTP backend. The default is T.
• max-redirects (fixnum)
  • The limit of redirections. The default is 5. If the redirection exceeds the limit, functions return the last response (not raise a condition).
• ssl-key-file, ssl-cert-file, ssl-key-password
  • for HTTPS connection
• stream
  • The stream to write an HTTP request. This is a way to reuse a connection and commonly used with :keep-alive T. This allows the caller to do connection pooling, etc. It is easier to just use :use-connection-pool t, which is the default, and let the dexador internals take care of this for you (only supported for usocket backends).
• verbose (boolean)
  • This option is for debugging. When T, it dumps the HTTP request headers.
• force-binary (boolean)
  • A flag for suppressing auto-decoding of the response body.

• want-stream (boolean)
  • A flag to get the response body as a stream.
• proxy (string)
  • for use proxy. defaults to the value of dex:*default-proxy* which defaults to the value of environment variables HTTPS_PROXY or HTTP_PROXY. Not supported on windows currently
• insecure (boolean)
  • To bypass SSL certificate verification (use at your own risk). The default is NIL, the value of *not-verify-ssl*.

[Function] request

(dex:request uri &key (method get) (version 1.1) content headers
             basic-auth cookie-jar (connect-timeout *default-connect-timeout*)
             (read-timeout *default-read-timeout*) (keep-alive t) (use-connection-pool t)
             (max-redirects 5) ssl-key-file ssl-cert-file ssl-key-password stream
             (verbose *verbose*) force-binary force-string want-stream proxy
             (insecure *not-verify-ssl*) ca-path)
;=> body
;   status
;   response-headers
;   uri
;   stream

Send an HTTP request to uri.

The body is an octet vector or a string if the Content-Type is text/*. If you always want it to return an octet vector, specify :force-binary as T.

The status is an integer which represents HTTP status code.

The response-headers is a hash table which represents HTTP response headers. Note that all hash keys are downcased like "content-type". If there's duplicate HTTP headers, those values are concatenated with a comma.

The uri is a QURI object which represents the last URI Dexador requested.

The stream is a usocket stream to communicate with the HTTP server if the connection is still alive and can be reused. This value may be NIL if :keep-alive is NIL or the server closed the connection with Connection: close header or you are using :use-connection-pool t which handles re-using the connections for you.

This function signals http-request-failed when the HTTP status code is 4xx or 5xx.

[Function] get

(dex:get uri &key version headers basic-auth cookie-jar keep-alive
         use-connection-pool connect-timeout read-timeout max-redirects
         force-binary force-string want-stream ssl-key-file
         ssl-cert-file ssl-key-password stream verbose proxy insecure
         ca-path)

[Function] post

(dex:post uri &key version content headers basic-auth cookie-jar
          keep-alive use-connection-pool connect-timeout read-timeout
          force-binary force-string want-stream ssl-key-file
          ssl-cert-file ssl-key-password stream verbose proxy insecure
          ca-path)

[Function] head

(dex:head uri &key version headers basic-auth cookie-jar connect-timeout
          read-timeout max-redirects ssl-key-file ssl-cert-file
          ssl-key-password stream verbose proxy insecure ca-path)

[Function] put

(dex:put uri &key version content headers basic-auth cookie-jar
         keep-alive use-connection-pool connect-timeout read-timeout
         force-binary force-string want-stream ssl-key-file
         ssl-cert-file ssl-key-password stream verbose proxy insecure
         ca-path)

[Function] patch

(dex:patch uri &key version content headers basic-auth cookie-jar
           keep-alive use-connection-pool connect-timeout read-timeout
           force-binary force-string want-stream ssl-key-file
           ssl-cert-file ssl-key-password stream verbose proxy insecure
           ca-path)

[Function] delete

(dex:delete uri &key version headers basic-auth cookie-jar keep-alive
            use-connection-pool connect-timeout read-timeout
            force-binary force-string want-stream ssl-key-file
            ssl-cert-file ssl-key-password stream verbose proxy insecure
            ca-path)

[Function] fetch

Send a GET request to URI and write the response body to the DESTINATION.

(dex:fetch uri destination &key (if-exists error) verbose proxy insecure)

Benchmark

• Server
  • Sakura VPS 1GB
  • nginx 1.2.7, KeepAlive On
• Client
  • MacBook Pro OS X Yosemite (CPU: 3GHz Intel Core i7, Memory: 8GB)
  • SBCL 1.2.9
• Downloads an HTML file (181 bytes).

Drakma

(time (dotimes (i 30) (drakma:http-request "http://files.8arrow.org/181B.html")))
Evaluation took:
  1.012 seconds of real time
  0.174742 seconds of total run time (0.148141 user, 0.026601 system)
  17.29% CPU
  1,683 forms interpreted
  500 lambdas converted
  3,027,928,949 processor cycles
  29,416,656 bytes consed

Dexador

(time (dotimes (i 30) (dex:get "http://files.8arrow.org/181B.html")))
Evaluation took:
  0.499 seconds of real time
  0.028057 seconds of total run time (0.019234 user, 0.008823 system)
  5.61% CPU
  56 forms interpreted
  16 lambdas converted
  1,494,851,690 processor cycles
  1,472,992 bytes consed

See Also

• fast-http
• cl-cookie
• QURI

Author

• Eitaro Fukamachi (e.arrows@gmail.com)

Copyright

Copyright (c) 2015 Eitaro Fukamachi (e.arrows@gmail.com)

License

Licensed under the MIT License.