Json - Anybus CompactCom 40 Network Manual

JSON

9 JSON
9.1 General Information
JSON is an acronym for JavaScript Object Notation and an open standard format for storing
and exchanging data in an organized and intuitive way. In Anybus CompactCom, it is used to
transmit data objects consisting of name - value pairs between the webserver in the Anybus
CompactCom and a web application. The object members are unordered, thus the value pairs
can appear in any order. JavaScripts are used to create dynamic web pages to present the val-
ues. Optionally, a callback may be passed to the GET-request for JSONP output.
JSON is more versatile than SSI in that you not only can read and write, but also change the
size and the look of the web page dynamically. A simple example of how to create a web page
is added at the end of this chapter.
9.1.1 Encoding
JSON requests shall be UTF-8 encoded. The module will interpret JSON requests as UTF-8 en-
coded, while all other HTTP requests will be interpreted as ISO-8859-1 encoded. All JSON re-
sponses, sent by the module, are UTF-8 encoded, while all other files sent by the web server
are encoded as stored in the file system.
9.1.2 Access
It is recommended to password protect the JSON resources. Add password protection by add-
ing a file called web_accs.cfg in the root directory (all web content will be protected). The file is
described in the "Web Server" section in this document.
9.1.3 Error Response
If the module fails to parse or process a request, the response will contain an error object with
an Anybus error code:
{
"error"
}
The Anybus error codes are listed in the Anybus CompactCom 40 Software Design Guide.
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