This is a sample chapter from Brad Stone s training e-rpg Powertools Stone on CGIDEV2 Get your copy of this important training now.

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1 Stone on CGIDEV2 This is a sample chapter from Brad Stone s training e-rpg Powertools Stone on CGIDEV2 Get your copy of this important training now. With Stone on CGIDEV2 RPG programmers quickly learn how to develop web applications using IBM's CGIDEV2 development tools with RPG. CGIDEV2, which is provided free of charge from IBM, is a powerful toolkit developed by Mel Rothman of the IBM eserver Custom Technology Center (ectc). It allows RPG programmers to easily create web applications with RPG. This course provides tools that make it a snap to write, test, debug, and maintain ILE-RPG IV CGI programs. Get your copy today. You will learn to: Download, install and configure the CGIDEV2 toolkit Create dynamic web output with RPG programs Store dynamic output in the Integrated File System (IFS) Easily read input from a web browser using an RPG program Use the built-in error handling, reporting and debugging features included in CGIDEV2 Write and read cookies in CGI applications using RPG Find resources, forums and discussion groups related to CGIDEV2 Avoid hard-coding of HTML, JavaScript and Style Sheets in your CGI applications Eliminate data replication to non-as/400 machines used for serving your AS/400 data Avoid programming with complicated CGI APIs Build fully functional interactive online applications Debug CGI applications easily with CGIDEV2's built in functionality Create your own e-store with shopping cart Develop dynamic RPG web apps with IBM's free toolkit and e-rpg Powertools Stone on CGIDEV2! Get your copy now!

2 Chapter 4. Data Manipulation When dealing with web data, you are governed by factors that are uncontrollable. For example, all data read from a web browser, whether is it part of the HTTP data stream, environment variables or input variables from a form, is initially in character form. Trying to use data such as the value of the CONTENT_LENGTH environment variable (used to obtain the length of data after a POST method of an HTML form) can lead to cumbersome or difficult to use code. You may need to use functions or APIs to convert the value into the required data type, in this case, numeric. You also may need to convert data from character to hexadecimal format, or vice versa. Both conversions can be tedious, especially if you re not familiar with or even aware of APIs that are available to perform the conversions. The CGIDEV2 toolkit provides several subprocedures that help you perform simple data translation, as well as check data for valid information. You will probably never use most of the subprocedures described in this chapter. The descriptions are included mainly because the subprocedures are used by other subprocedures included in the CGIDEV2 toolkit to perform easy translations and data validation. But because the data manipulation subprocedures are available for your use, I thought it would be a good idea to cover them, even if this information is brief. Stone on CGIDEV2 4-1

3 4.1. Char2Hex The Char2Hex subprocedure is used to convert character data into its hexadecimal representation. This subprocedure is handy if you ever need to encode data into hex strings. For example, when you re building URLs that contain a query string variable, it is required that you convert special characters (non alphabetic) into a hex encoded representation preceded by the percent (%) sign. Char2Hex parameters The parameters for the Char2Hex subprocedure are shown in Table 4-1. Table 4-1: Char2Hex parameters. Input String Char(16000) The character input string This parameter contains the character string that you want to convert to the hexadecimal format. The Char2Hex subprocedure returns a string with a maximum length of 32,000 bytes. The string contains the hexadecimal representation of the character string passed in as an input variable. For example, if passed the character string ABC, the returned result is C1C2C Stone on CGIDEV2

4 4.2. Hex2Char The Hex2Char subprocedure does exactly the opposite of the previously described Char2Hex subprocedure. It accepts a string representing a hexadecimal value and converts it to its character string equivalent. Hex2Char parameters The parameters for the Hex2Char subprocedure are shown in Table 4-2. Table 4-2: Hex2Char parameters. Input String Char(32000) The hexadecimal input string The input string is a hexadecimal string that you want to convert to a character string. The value returned by the Hex2Char subprocedure is a character string. For example, if the value C1C2C3 is passed to the Hex2Char subprocedure, the value returned is ABC. Stone on CGIDEV2 4-3

5 4.3. C2N The C2N subprocedure converts a character string to a floating-point representation. This can be useful in situations that require a result in floating-point format. C2N parameters The parameters used by the C2N subprocedure are shown in Table 4-3. Table 4-3: C2N parameters. Input String Char(32) The character input string This parameter contains a character representation of a numeric value. For example, the character string literal is a valid input string that will be converted. The C2N subprocedure returns a floating-point (data type f) numeric value representing the character string passed in. If an error occurs during processing, the value returned is zero. 4-4 Stone on CGIDEV2

6 4.4. C2N2 Data Manipulation The C2N2 subprocedure is similar to the C2N subprocedure in that it accepts a character string and returns the numeric value. However, instead of returning a floating point data type, a packed decimal (length 30,9) is returned to the caller. Because RPG programmers are more accustomed to working with packed numeric data instead of floating point values, this subprocedure is more likely to be useful in your applications. This subprocedure is not only useful for CGI development, but there may be cases in your every day applications where this subprocedure will come in handy. C2N2 parameters The parameters for the C2N2 subprocedure are shown in Table 4-4. Table 4-4: C2N2 parameters. Input String Char(32) The character input string This parameter contains a character representation of a numeric value. For example, the character string literal is a valid input string that will be converted. The C2N2 subprocedure returns a packed decimal numeric value representing the character string passed in. The size of the returned data is 30 digits with 9 decimal places. Stone on CGIDEV2 4-5

7 4.5. ChkNbr There may be times when you may want to check a character string to see if it contains only valid numbers before trying to convert the character string into its numeric representation. The ChkNbr subprocedure accepts a string and verifies that it contains only the following characters: Digits from 0 9 Decimal point character Sign character ChkNbr returns an array of seven indicators, each meaning something different if turned on. ChkNbr parameters The parameters used with the ChkNbr subprocedure are shown in Table 4-5. Input String Char(32) The character input string Maximum Digits Integer(10) The maximum number of digits to the left of the decimal point. This parameter is optional. Add Messages Logical A flag to indicate if messages should be written to the message list if errors are found. This parameter is optional. Field Description Negative is Error Table 4-5: ChkNbr parameters. Char(32) Logical The field description that should be used for errors written to the message list. A flag to indicate if negative numbers should be considered an error. The single input parameter should be a character representation of a numeric value. For example, would be a valid input string. Maximum digits An integer value that represents the maximum number of digits the number can have to the left of the decimal point. This parameter is optional. If not passed, the value of zero is assumed, which means that this check should be ignored. Add messages This parameter should contain a logical value (*ON or *OFF) that will tell the system to write messages to the message list if errors are found. The message list is a list of messages used by the CGIDEV2 package and is described in a later chapter. This parameter is optional. If omitted the value of *OFF will be used to indicate that messages are not written to the message list. Field description If the Add messages parameter is set to *ON, this parameter should specify the field description to use if an error is encountered and that error is written to the message list. This parameter is optional. A value of blank is used if it is omitted. 4-6 Stone on CGIDEV2

8 Negative is error This logical parameter (*ON or *OFF) is used to tell the ChkNbr subprocedure if it should consider negative numbers an error. This parameter is optional. If omitted, negative numbers will not be considered in error. The ChkNbr subprocedure returns an array of indicators, or logical values, that represent certain checks that were made during execution. The indicators and their descriptions (in order) are as follows: Indicator 1 If *ON, one or more errors exist. If *OFF, then the string passed in is a valid number. Indicator 2 If *ON, the value passed in is not a valid numeric representation. This may also indicate a negative sign in an incorrect position, for example, in the middle of the string. Indicator 3 If *ON, the input string contains more than one decimal place. Indicator 4 If *ON, the input string contains multiple signs, both leading and trailing. Indicator 5 If *ON, the input string contains invalid numeric characters or a length of zero. Indicator 6 If *ON, the input string contains too many digits to the left of the decimal place. Indicator 7 If *ON, there are no errors but the value is less than zero. Stone on CGIDEV2 4-7

9 4.6. XlatwCCSIDs The XlatwCCSIDs subprocedure is used to convert data from one Coded Character Set Identifier (CCSID) to another. This procedure can also be used to convert data to or from the EBCDIC representation. XlatwCCSIDs parameters The parameters for the XlatwCCSIDs subprocedure are shown in Table 4-6. To EBCDIC Logical A flag to indicate if the data should be converted to or from EBCDIC Input String Char(32767) The input string that is to be converted From CCSID Unsigned Integer(10) The original CCSID. This parameter is optional. To CCSID Unsigned Integer(1) The target CCSID. This parameter is optional. Table 4-6: XlatwCCSIDs parameters. To EBCDIC This parameter is used to indicate if the input data should be converted to or from EBCDIC. If this value is *ON, the conversion to EBCDIC is performed. Otherwise, the conversion will be from EBCDIC. The input string parameter contains the data that you want to convert. From CCSID Specify the original CCSID that the data is currently represented by. This parameter is optional. If omitted, the CCSID value specified in either the CGI_EBCDIC_CCSID or CGI_ASCII_CCSID environment variable is used, depending on if the To EBCDIC parameter is *ON or *OFF. To CCSID Specify the target CCSID that the data will be converted into. This parameter is optional. If omitted, the CCSID value specified in either the CGI_EBCDIC_CCSID or CGI_ASCII_CCSID environment variable is used, depending on if the To EBCDIC parameter is *ON or *OFF. The XlatwCCSIDs subprocedure returns the converted string to the calling program. 4-8 Stone on CGIDEV2

10 4.7. Uppify Data Manipulation The Uppify subprocedure performs the simple task of translating any lower case characters in a string to upper case. This is another example of a subprocedure that may come in very handy outside of your CGI applications. Uppify parameters The parameters for the Uppify subprocedure are shown in Table 4-7. Table 4-7: Uppify parameters. Input String Char(32767) The string to be converted to upper case This parameter contains the string that you want to covert to upper case. The Uppify subprocedure returns the input string in all upper case to the calling program. Stone on CGIDEV2 4-9

11 4.8. FixMixed The FixMixed subprocedure is used mainly by the GetInput subprocedure described in Chapter 3. It is used to fix data represented in a mixed format. FixMixed parameters The parameters for the FixMixed subprocedure are shown in Table 4-8. String Char(32767) Input/Output The input string containing the data to be converted from mixed to EBCDIC. This field will also contain the fixed string after the call. Table 4-8: FixMixed parameters. String String Length Integer(10) The length of the input or output string. The string parameter in the FixMixed subprocedure plays two roles: It is used as an input parameter to pass the string containing the mixed data into the subprocedure. After the call has completed, this variable will contain the fixed string. String length The string length parameter also plays a dual role: When calling the FixMixed subprocedure, the parameter contains the length of the input string. After the call has completed, the parameter contains the length of the new string returned in the first parameter Stone on CGIDEV2

12 Stone on CGIDEV2 This is a sample chapter from Brad Stone s training e-rpg Powertools Stone on CGIDEV2 Get your copy of this important training now. With Stone on CGIDEV2 RPG programmers quickly learn how to develop web applications using IBM's CGIDEV2 development tools with RPG. CGIDEV2, which is provided free of charge from IBM, is a powerful toolkit developed by Mel Rothman of the IBM eserver Custom Technology Center (ectc). It allows RPG programmers to easily create web applications with RPG. This course provides tools that make it a snap to write, test, debug, and maintain ILE-RPG IV CGI programs. Get your copy today. You will learn to: Download, install and configure the CGIDEV2 toolkit Create dynamic web output with RPG programs Store dynamic output in the Integrated File System (IFS) Easily read input from a web browser using an RPG program Use the built-in error handling, reporting and debugging features included in CGIDEV2 Write and read cookies in CGI applications using RPG Find resources, forums and discussion groups related to CGIDEV2 Avoid hard-coding of HTML, JavaScript and Style Sheets in your CGI applications Eliminate data replication to non-as/400 machines used for serving your AS/400 data Avoid programming with complicated CGI APIs Build fully functional interactive online applications Debug CGI applications easily with CGIDEV2's built in functionality Create your own e-store with shopping cart Develop dynamic RPG web apps with IBM's free toolkit and e-rpg Powertools Stone on CGIDEV2! Get your copy now!