Adobe 38043740 Developing Applications - Page 380

General character encoding issues, Locale-specific content, Input data from URLs and HTML forms

Page 380 highlights

DEVELOPING COLDFUSION 9 APPLICATIONS 375 Developing CFML Applications • CORBA • Searching and indexing General character encoding issues Applications developed for earlier versions of ColdFusion that assumed that the character length of a string was the same as the byte length might produce errors in ColdFusion. The byte length of a string depends on the character encoding. Locale-specific content Generating multilocale content In an application that supports users in multiple locales and produces output that is specific to multiple locales, you call the SetLocale function in every request to set the locale for that specific request. When processing has completed, the locale should be set back to its previous value. One useful technique is to save the user's desired locale in a Session variable once the user has selected it, and use the Session variable value to set the locale for each user request during the session. Supporting the euro The euro is the currency of many European countries, and ColdFusion supports the reading and writing of correctly formatted euro values. Unlike other supported currencies, the euro is not tied to any single country (or locale). The LSCurrencyFormat and LSParseCurrency functions rely on the underlying JVM for their operations, and the rules used for currencies depend on the JVM. For Sun JVMs, the 1.3 releases did not support euros and used the older country-specific currencies. The 1.4 releases use euros for all currencies that are in the euro zone as of 2002. If you are using a JVM that does not support the euro, use the LSEuroCurrencyFormat and LSParseEuroCurrency functions to format and parse euro values in locales that use euros as their currency. Input data from URLs and HTML forms A web application server receives character data from request URL parameters or as form data. The HTTP 1.1 standard only allows US-ASCII characters (0-127) for the URL specification and for message headers. This requires a browser to encode the non-ASCII characters in the URL, both address and parameters, by escaping (URL encoding) the characters using the "%xx" hexadecimal format. URL encoding, however, does not determine how the URL is used in a web document. It only specifies how to encode the URL. Form data uses the message headers to specify the encoding used by the request (Content headers) and the encoding used in the response (Accept headers). Content negotiation between the client and server uses this information. There are several techniques for handling both URL and form data entered in different character encodings. Handling URL strings URL requests to a server often contain name-value pairs as part of the request. For example, the following URL contains name-value pairs as part of the URL: http://company.com/prod_page.cfm?name=Stephen;ID=7645 As discussed previously, URL characters entered using any character encoding other than US-ASCII are URL-encoded in a hexadecimal format. However, by default, a web server assumes that the characters of a URL string are single-byte characters. Last updated 1/20/2012

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DEVELOPING
COLDFUSION 9 APPLICATIONS
Developing CFML Applications
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General character encoding issues
Applications developed for earlier versions of ColdFusion that assumed that the character length of a string was the
same as the byte length might produce errors in ColdFusion. The byte length of a string depends on the character
encoding.
Locale-specific content
Generating multilocale content
In an application that supports users in multiple locales and produces output that is specific to multiple locales, you
call the
SetLocale
function in every request to set the locale for that specific request. When processing has completed,
the locale should be set back to its previous value. One useful technique is to save the user’s desired locale in a Session
variable once the user has selected it, and use the Session variable value to set the locale for each user request during
the session.
Supporting the euro
The euro is the currency of many European countries, and ColdFusion supports the reading and writing of correctly
formatted euro values. Unlike other supported currencies, the euro is not tied to any single country (or locale). The
LSCurrencyFormat and LSParseCurrency functions rely on the underlying JVM for their operations, and the rules
used for currencies depend on the JVM. For Sun JVMs, the 1.3 releases did not support euros and used the older
country-specific currencies. The 1.4 releases use euros for all currencies that are in the euro zone as of 2002. If you are
using a JVM that does not support the euro, use the
LSEuroCurrencyFormat
and
LSParseEuroCurrency
functions
to format and parse euro values in locales that use euros as their currency.
Input data from URLs and HTML forms
A web application server receives character data from request URL parameters or as form data.
The HTTP 1.1 standard only allows US-ASCII characters (0-127) for the URL specification and for message headers.
This requires a browser to encode the non-ASCII characters in the URL, both address and parameters, by escaping
(URL encoding) the characters using the “%xx” hexadecimal format. URL encoding, however, does not determine how
the URL is used in a web document. It only specifies how to encode the URL.
Form data uses the message headers to specify the encoding used by the request (Content headers) and the encoding
used in the response (Accept headers). Content negotiation between the client and server uses this information.
There are several techniques for handling both URL and form data entered in different character encodings.
Handling URL strings
URL requests to a server often contain name-value pairs as part of the request. For example, the following URL
contains name-value pairs as part of the URL:
http://company.com/prod_page.cfm?name=Stephen;ID=7645
As discussed previously, URL characters entered using any character encoding other than US-ASCII are URL-encoded
in a hexadecimal format. However, by default, a web server assumes that the characters of a URL string are single-byte
characters.