Is there any default media type when the query is not specified with any supported media types in RESTCONF ?
No. There is no standard default. This is server implementation dependent, so do not rely on it.
From draft-ietf-netconf-restconf-17, Section 5.3, Message Encoding:
The server MUST support the "Accept" header field and "406 Not
Acceptable" status-line, as defined in [RFC7231]. The response
output content encoding formats that the client will accept are
identified with the Accept header field in the request. If it is not
specified, the request input encoding format SHOULD be used, or the
server MAY choose any supported content encoding format.
If there was no request input, then the default output encoding is
XML or JSON, depending on server preference. File extensions encoded
in the request are not used to identify format encoding.
And from draft-ietf-netconf-restconf-17, Section 7.1, Error Response Message:
The client SHOULD specify the desired encoding(s) for response
messages by specifying the appropriate media-type(s) in the Accept
header. If the client did not specify an Accept header, then the
same structured syntax name suffix used in the request message SHOULD
be used, or the server MAY choose any supported message encoding
format. If there is no request message the server MUST select
"application/yang-data+xml" or "application/yang-data+json",
depending on server preference.
The final RFC stood by the draft, just as #predi said:
On Message Encoding, Section 5.2:
If there was no request input, then the default output encoding is
XML or JSON, depending on server preference. File extensions encoded
in the request are not used to identify format encoding.
And Error Message Response, Section 7.1
If the client did not specify an "Accept" header, then the same
structured syntax name suffix used in the request message SHOULD be
used, or the server MAY choose any supported message-encoding
format. If there is no request message, the server MUST select
"application/yang-data+xml" or "application/yang-data+json",
depending on server preference.
Related
I am trying to follow the guide to generate Oauth authentication tokens for YAHOO DSP API.
Base64 encoding is a way of encoding binary data into text so that it can be easily transmitted across a network without error.
In this step, you will take the client ID and client secret that the YDN console generated for you and encode them using the base64 protocol. You can use an online encoding service like base64encode.org.
No matter which service you use, ensure that no spaces are appended to the CLIENT_ID and CLIENT_SECRET keys and separate the CLIENT_ID and CLIENT_SECRET with a colon, i.e. CLIENT_ID:CLIENT_SECRET.
The generated value will now be referenced as ENCODED(CLIENT_ID:CLIENT_SECRET) in this guide.
An example is given:
CLIENT_ID = dj0yJmk9N2pIazlsZk1iTzIxJmQ9WVdrOWVEUmpVMFpWTXpRbWNHbzlNQS0tJnM9Y29uc3VtZXJzZWNyZXQmeD00NA–
CLIENT_SECRET= a7e13ea3740b933496d88755ff341bfb824805a6
AUTHORIZATION = ZGoweUptazlOMnBJYXpsc1prMWlUekl4Sm1ROVdWZHJPV1ZFVW1wVk1GcFdUWHBSYldOSGJ6bE5RUzB0Sm5NOVkyOXVjM1Z0WlhKelpXTnlaWFFtZUQwME5BLS06YTdlMTNlYTM3NDBiOTMzNDk2ZDg4NzU1ZmYzNDFiZmI4MjQ4MDVhNg==
Using the recommended website I get the wrong AUTHORIZATION.
I have tried both encoding the whole thing at once ie. encode(CLIENT_ID:CLIENT_SECRET), and each element individually encode(CLIENT_ID):encode(CLIENT_SECRET).
Attempt encoding whole thing:
ZGoweUptazlOMnBJYXpsc1prMWlUekl4Sm1ROVdWZHJPV1ZFVW1wVk1GcFdUWHBSYldOSGJ6bE5RUzB0Sm5NOVkyOXVjM1Z0WlhKelpXTnlaWFFtZUQwME5B4oCTOiBhN2UxM2VhMzc0MGI5MzM0OTZkODg3NTVmZjM0MWJmYjgyNDgwNWE2
Attempt encoding each element:
ZGoweUptazlOMnBJYXpsc1prMWlUekl4Sm1ROVdWZHJPV1ZFVW1wVk1GcFdUWHBSYldOSGJ6bE5RUzB0Sm5NOVkyOXVjM1Z0WlhKelpXTnlaWFFtZUQwME5B4oCT:YTdlMTNlYTM3NDBiOTMzNDk2ZDg4NzU1ZmYzNDFiZmI4MjQ4MDVhNg==
Expected result:
ZGoweUptazlOMnBJYXpsc1prMWlUekl4Sm1ROVdWZHJPV1ZFVW1wVk1GcFdUWHBSYldOSGJ6bE5RUzB0Sm5NOVkyOXVjM1Z0WlhKelpXTnlaWFFtZUQwME5BLS06YTdlMTNlYTM3NDBiOTMzNDk2ZDg4NzU1ZmYzNDFiZmI4MjQ4MDVhNg==
The difference between 'each element' and the expected result is only a few characters corresponding to the end of client_ID and the colon.
B4oCT: should be BLS06.
Links to full documentation:
https://developer.yahoo.com/dsp/api/docs/authentication/tokens.html
https://developer.yahoo.com/dsp/api/docs/traffic/info/sandbox.html
Update:
The final character of Client_ID is '–' . This is some sort of non-standard character that is interpreted as two dashes i.e.'--' in utf-8 and windows 1258.
One different, TO NOTE is, that when you decrypt the expected output you will get your client id as
dj0yJmk9N2pIazlsZk1iTzIxJmQ9WVdrOWVEUmpVMFpWTXpRbWNHbzlNQS0tJnM9Y29uc3VtZXJzZWNyZXQmeD00NA--
instead of
dj0yJmk9N2pIazlsZk1iTzIxJmQ9WVdrOWVEUmpVMFpWTXpRbWNHbzlNQS0tJnM9Y29uc3VtZXJzZWNyZXQmeD00NA–
NOTE, there are two "-" at the end.
OAuth client auth token is always generated using Base64 encoding with following format
Base64_Encoding(CLIENT_ID:CLIENT_SECRET)
Most of the usage perform this Base64 encoding with encoding type as "UTF-8".
It looks like, Yahoo requires this token with different encoding. On "https://www.base64encode.org/" if you try to encode your "CLIENT_ID:CLIENT_SECRET" with "Windows-1254" as destination charset, you will receive the expected result. So, it looks like both encoding and decoding here is done keeping "Windows-1254" charset in place.
In windows, I get:
#content_type="application/octet-stream"
Full trace:
"attachments_attributes"=>{"0"=>{"attachment"=>#<ActionDispatch::Http::UploadedFile:0x007f7bb52becc8 #original_filename="ms_document.doc", #content_type="application/octet-stream", #headers="Content-Disposition: form-data; name=\"post[attachments_attributes][0][attachment]\"; filename=\"doc\"\r\nContent-Type: application/octet-stream\r\n", #tempfile=#<Tempfile:/tmp/RackMultipart20160108-8859-x51qhj>>}}}
In Linux I get:
#content_type="application/msword"
Full trace:
"attachments_attributes"=>{"0"=>{"attachment"=>#<ActionDispatch::Http::UploadedFile:0x007f7bb5d585d0 #original_filename="ms_document.doc", #content_type="application/msword", #headers="Content-Disposition: form-data; name=\"post[attachments_attributes][0][attachment]\"; filename=\"doc.doc\"\r\nContent-Type: application/msword\r\n", #tempfile=#<Tempfile:/tmp/RackMultipart20160108-8859-9m1xgv>>}}}
The question is, why I received different #content_type while I'm uploading the same file but only different OS.
I'm using:
rails 3
paperclip '4.3.2'
HTTP specification here states that
When an entity-body is included with a message, the data type of that body is determined via the header fields Content-Type and Content- Encoding. These define a two-layer, ordered encoding model:
entity-body := Content-Encoding( Content-Type( data ) ) Content-Type
specifies the media type of the underlying data. Content-Encoding may
be used to indicate any additional content codings applied to the
data, usually for the purpose of data compression, that are a property
of the requested resource. There is no default encoding.
Any HTTP/1.1 message containing an entity-body SHOULD include a
Content-Type header field defining the media type of that body. If and
only if the media type is not given by a Content-Type field, the
recipient MAY attempt to guess the media type via inspection of its
content and/or the name extension(s) of the URI used to identify the
resource. If the media type remains unknown, the recipient SHOULD
treat it as type "application/octet-stream".
In your case, this might have happened, beacuse the server on which the file had been sent/uploaded wasn't able to determine the type of file, because the browser might have not set the Content-Type in HTTP message when sending the file.
It depends on which browser and OS you are using. Browser on windows might be not setting the content type.
I am Working on MQTT communication using Paho and Mosqitto. We have to support both model of serialization - xml and json. So I am looking How to identify the content type or payload type in MQTT. Is there something similar HTTP Content-Type in MQTT to identify it quickly ?
Content-Type : application/json
Content-Type : application/xml
Thanks
No, MQTT payloads are just byte arrays and there is no space in the headers (because MQTT is designed to be as light weight as possible on the network). Anything else is down to the application to implement with in the payload.
You could use multiple topics to show the difference.
e.g. foo/bar/xml or foo/bar/json and subscribe to foo/bar/+ which will match both and then switch based on the topic.
or just test the first char of the payload, '{' = json '<' = xml
2021 answer
MQTT 5.0 introduced the concept of Properties. Basically, properties are UTF-8 string key-value pairs that you can add to an MQTT packet. The new specification also defines payload-format and content-type to convey information about the MIME type contained in the payload. So in principle, you can use this property in your application much like in HTTP you use Content-Type header.
I use AFHTTPRequestOperationManager to send HTTP request, and have some information put in the HTTP custom header, named "X-AKey".
I confirmed the header name by:
NSLog(#"%#", manager.requestSerializer.HTTPRequestHeaders);
Then, I captured the outgoing message, and found that the header name has changed to "HTTP_X_AKEY".
I've searched some questions, and found that this might be a standard way of naming custom header: "Meta-variables with names beginning with "HTTP_" contain values read from the client request header fields, if the protocol used is HTTP. The HTTP header field name is converted to upper case, has all occurrences of "-" replaced with "" and has "HTTP" prepended to give the meta-variable name."
Nevertheless, my question is: CAN I send a message with a custom header name exactly as I specified? That is, in my case, "X-AKey" instead of "HTTP_X_AKEY"?
(PS: For real applications, if both the client and server are negotiated to use the 'HTTP_xxx' format, there won't be any problem. I'm just curious about the answer for now.)
Thanks.
Try this:
[manager.requestSerializer setValue:#"SomeValue" forHTTPHeaderField:#"SomeHeaderField"]
I'm very new in Erlang world and I'm trying to write a client for the Twitter Stream API. I'm using httpc:request to make a POST request and I constantly get 401 error, I'm obviously doing something wrong with how I'm sending the request... What I have looks like this:
fetch_data() ->
Method = post,
URL = "https://stream.twitter.com/1.1/statuses/filter.json",
Headers = "Authorization: OAuth oauth_consumer_key=\"XXX\", oauth_nonce=\"XXX\", oauth_signature=\"XXX%3D\", oauth_signature_method=\"HMAC-SHA1\", oauth_timestamp=\"XXX\", oauth_token=\"XXX-XXXXX\", oauth_version=\"1.0\"",
ContentType = "application/json",
Body = "{\"track\":\"keyword\"}",
HTTPOptions = [],
Options = [],
R = httpc:request(Method, {URL, Headers, ContentType, Body}, HTTPOptions, Options),
R.
At this point I'm confident there's no issue with the signature as the same signature works just fine when trying to access the API with curl. I'm guessing there's some issue with how I'm making the request.
The response I'm getting with the request made the way demonstrated above is:
{ok,{{"HTTP/1.1",401,"Unauthorized"},
[{"cache-control","must-revalidate,no-cache,no-store"},
{"connection","close"},
{"www-authenticate","Basic realm=\"Firehose\""},
{"content-length","1243"},
{"content-type","text/html"}],
"<html>\n<head>\n<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>\n<title>Error 401 Unauthorized</title>\n</head>\n<body>\n<h2>HTTP ERROR: 401</h2>\n<p>Problem accessing '/1.1/statuses/filter.json'. Reason:\n<pre> Unauthorized</pre>\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n</body>\n</html>\n"}}
When trying with curl I'm using this:
curl --request 'POST' 'https://stream.twitter.com/1.1/statuses/filter.json' --data 'track=keyword' --header 'Authorization: OAuth oauth_consumer_key="XXX", oauth_nonce="XXX", oauth_signature="XXX%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="XXX", oauth_token="XXX-XXXX", oauth_version="1.0"' --verbose
and I'm getting the events just fine.
Any help on this would be greatly appreciated, new with Erlang and I've been pulling my hair out on this one for quite a while.
There are several issues with your code:
In Erlang you are encoding parameters as a JSON body while with curl, you are encoding them as form data (application/x-www-form-urlencoded). Twitter API expects the latter. In fact, you get a 401 because the OAuth signature does not match, as you included the track=keyword parameter in the computation while Twitter's server computes it without the JSON body, as it should per OAuth RFC.
You are using httpc with default options. This will not work with the streaming API as the stream never ends. You need to process results as they arrive. For this, you need to pass {sync, false} option to httpc. See also stream and receiver options.
Eventually, while httpc can work initially to access Twitter streaming API, it brings little value to the code you need to develop around it to stream from Twitter API. Depending on your needs you might want to replace it a simple client directly built on ssl, especially considering it can decode HTTP packets (what is left for you is the HTTP chunk encoding).
For example, if your keywords are rare, you might get a timeout from httpc. Besides, it might be easier to update the list of keywords or your code with no downtime without httpc.
A streaming client directly based on ssl could be implemented as a gen_server (or a simple process, if you do not follow OTP principles) or even better a gen_fsm to implement reconnection strategies. You could proceed as follows:
Connect using ssl:connect/3,4 specifying that you want the socket to decode the HTTP packets with {packet, http_bin} and you want the socket to be configured in passive mode {active, false}.
Send the HTTP request packet (preferably as an iolist, with binaries) with ssl:send/2,3. It shall spread on several lines separated with CRLF (\r\n), with first the query line (GET /1.1/statuses/filter.json?... HTTP/1.1) and then the headers including the OAuth headers. Make sure you include Host: stream.twitter.com as well. End with an empty line.
Receive the HTTP response. You can implement this with a loop (since the socket is in passive mode), calling ssl:recv/2,3 until you get http_eoh (end of headers). Note down whether the server will send you data chunked or not by looking at the Transfer-Encoding response header.
Configure the socket in active mode with ssl:setopts/2 and specify you want packets as raw and data in binary format. In fact, if data is chunked, you could continue to use the socket in passive mode. You could also get data line by line or get data as strings. This is a matter of taste: raw is the safest bet, line by line requires that you check the buffer size to prevent truncation of a long JSON-encoded tweet.
Receive data from Twitter as messages sent to your process, either with receive (simple process) or in handle_info handler (if you implemented this with a gen_server). If data is chunked, you shall first receive the chunk size, then the tweets and the end of the chunk eventually (cf RFC 2616). Be prepared to have tweets that spread on several chunks (i.e. maintain some kind of buffer). The best here is to do the minimum decoding in this process and send tweets to another process, possibly in binary format.
You should also handle errors and socket being closed by Twitter. Make sure you follow Twitter's guidelines for reconnection.