XSLTools

README.txt

594:48f5468f15f3
2007-06-10 paulb [project @ 2007-06-10 22:49:02 by paulb] Improved commentary.
     1 Introduction
     2 ------------
     3 
     4 XSLTools is a collection of modules and packages facilitating the development
     5 of applications based on XML, XSL stylesheets and transformations, notably Web
     6 applications involving complicated Web forms potentially consisting of
     7 editable hierarchical structures and potentially involving "live" or "in-page"
     8 dynamic updates to portions of those Web forms.
     9 
    10 Quick Start
    11 -----------
    12 
    13 Try running the demo:
    14 
    15 python tools/demo.py
    16 
    17 An introductory guide to creating applications can be found in the docs
    18 directory - see docs/index.html for the start page.
    19 
    20 Contact, Copyright and Licence Information
    21 ------------------------------------------
    22 
    23 The current Web page for XSLTools at the time of release is:
    24 
    25 http://www.boddie.org.uk/python/XSLTools.html
    26 
    27 Copyright and licence information can be found in the docs directory - see
    28 docs/COPYING.txt, docs/LICENCE.txt and docs/LICENCE-Sarissa.txt for more
    29 information.
    30 
    31 Dependencies
    32 ------------
    33 
    34 XSLTools has the following basic dependencies:
    35 
    36 Packages                    Release Information
    37 --------                    -------------------
    38 
    39 libxml2dom                  0.4.3
    40 libxml2 and libxslt         Some combinations may not be reliable!
    41                             Tested with libxml2 2.6.17 and libxslt 1.1.12
    42                             Tested with libxml2 2.6.27 and libxslt 1.1.20
    43 
    44 The example Web applications require WebStack (release 1.2.3 or later).
    45 The example PyQt applications have been tested with PyQt 3.15.
    46 
    47 New in XSLTools 0.4.5 (Changes since XSLTools 0.4.4)
    48 ----------------------------------------------------
    49 
    50   * Fixed the result of transformations in XSLOutput: proper document nodes
    51     are now produced.
    52   * Added an XSLForms.Resources.Login module which provides resources to
    53     support login screens and redirects.
    54   * Fixed newlines in the attributes created from fields in XSLForms: CR
    55     characters are no longer included since this caused the doubling up of
    56     newlines in Firefox.
    57 
    58 New in XSLTools 0.4.4 (Changes since XSLTools 0.4.3)
    59 ----------------------------------------------------
    60 
    61   * Fixed translation selection for the template:i18n annotation attribute,
    62     not just for the template:i18n extension function - more apologies for
    63     resulting output changes!
    64   * Improved the template fixing stylesheet and added some documentation for
    65     the script and the related expr-prefix attribute.
    66   * Introduced WebStack 1.2.2 EncodingSelector and encoding changes.
    67   * Added docstring and return value for the write_month_to_document function
    68     in XSLTools.XMLCalendar.
    69 
    70 New in XSLTools 0.4.3 (Changes since XSLTools 0.4.2)
    71 ----------------------------------------------------
    72 
    73   * Fixed translation selection when an unsupported locale is specified,
    74     choosing the first locale as the default (rather than exposing the values
    75     themselves as translations). Note that this is an unfortunate and subtle
    76     change which may affect application output - apologies are hereby offered!
    77 
    78 New in XSLTools 0.4.2 (Changes since XSLTools 0.4.1)
    79 ----------------------------------------------------
    80 
    81   * Added a content type check in the XSLFormsResource class, permitting
    82     non-form-based resources to access the raw request data, rather than have
    83     the data processed unsuccessfully and consequently discarded.
    84   * Added a script and a function to fix template namespaces after editing in
    85     a careless editor.
    86   * Changed libxml2mod and libxsltmod import details to try libxmlmods -
    87     suggested by Lucian Wischik for libxml2dom.
    88 
    89 New in XSLTools 0.4.1 (Changes since XSLTools 0.4)
    90 --------------------------------------------------
    91 
    92   * Made translations specified using the template:i18n annotation take
    93     priority over template:value annotations.
    94   * Added expression-based template:i18n annotations, and provided fallback
    95     output for such translations based on the value of the evaluated
    96     expression.
    97 
    98 New in XSLTools 0.4 (Changes since XSLTools 0.3.1)
    99 --------------------------------------------------
   100 
   101   * Changed the preparation of templates to produce rule-based output
   102     stylesheets, thus permitting recursive templates. This requires an extra
   103     expr-prefix annotation to be used in certain kinds of templates.
   104   * Added a recursive template example application.
   105   * Changed fragment production to use original template documents instead of
   106     output stylesheets.
   107   * Changed the in_page_resources attribute to provide the output identifier,
   108     thus changing the prepare_fragment method in Web resources so that only
   109     the fragment identifier needs to be supplied.
   110   * Added the XSLForms.Resources.WebResources.prepare_resources method for the
   111     preparation of initialiser and output stylesheets before an application is
   112     run.
   113   * Changed selectors to not automatically create elements in the form data
   114     document unless requested to do so. Introduced a Form.get_selector
   115     method in XSLForms.Fields.
   116   * Permitted the creation of hierarchies of elements in
   117     XSLForms.Utils.add_elements.
   118   * Introduced dynamic parameter evaluation for multiple-choice fields in
   119     order to support sources of multiple-choice values which reside in the
   120     form data document itself.
   121   * Added the FixNamespace.xsl stylesheet to correct documents saved by HTML
   122     editors which strip namespace prefixes.
   123   * Fixed filesystem encoding issues in the Candidate example; fixed language
   124     preference access in the Configurator and VerySimple examples.
   125   * Changed the BaseHTTPRequestHandler version of the Candidate example to
   126     store data in a subdirectory of the current working directory, thus
   127     allowing the demonstration application to work after package installation.
   128 
   129 New in XSLTools 0.3.1 (Changes since XSLTools 0.3)
   130 --------------------------------------------------
   131 
   132   * Fixed copyright and licensing information.
   133 
   134 New in XSLTools 0.3 (Changes since XSLTools 0.2)
   135 ------------------------------------------------
   136 
   137   * Introduced copying of multiple-choice value element contents so that
   138     option element labels can differ from the underlying values.
   139   * Added internationalisation support, providing the template:i18n annotation
   140     and the template:i18n extension function.
   141   * Updated the documentation to cover the above new features.
   142   * Fixed non-GET/POST request method handling in WebResources.
   143   * Added the xslform_preparemacro.py script.
   144   * Added an experimental template:range extension function.
   145 
   146 New in XSLTools 0.2 (Changes since XSLTools 0.1)
   147 ------------------------------------------------
   148 
   149   * Made a new XSLTools package and moved XSLOutput into it.
   150   * Improved serialisation of transformation results so that output options
   151     are observed (in some cases, at least).
   152   * Fixed stylesheet and reference document paths so that libxslt should not
   153     now become confused by ambiguous relative paths.
   154   * Added expression parameters to XSLOutput.Processor so that in-document
   155     data can be used to, for example, initialise multiple-choice field values.
   156   * Added input/initialiser support so that input documents can be tidied or
   157     initialised using information from the template.
   158   * Added template:init for use with template:element in XSLForms to control
   159     element initialisation where necessary.
   160   * Added special high-level "macro" attributes (eg. template:attribute-field)
   161     which should make templates easier to write and maintain.
   162   * Added template:if to XSLForms, providing conditional output of annotated
   163     elements.
   164   * Added set_document to XSLForms.Fields.Form.
   165   * Added prepare_parameters to the XSLFormsResource class in the
   166     XSLForms.Resources.WebResources module.
   167   * Added element-path, url-encode and choice XSLForms extension functions.
   168   * Improved Unicode support in the XSLForms extension functions.
   169   * Changed in-page requests to contain proper POST data.
   170   * Fixed checkbox and radiobutton value detection in XSLForms.js.
   171   * Updated the code to work with WebStack 1.0 changes and adopted the
   172     new-style WebStack demonstration mechanism.
   173   * Added XMLCalendar and XMLTable (to the XSLTools package).
   174   * Added a dictionary (or word lookup) example application.
   175   * Added a job candidate profile (or CV editor) example application.
   176   * Added a template attribute reference and an XSLFormsResource guide to the
   177     documentation.
   178   * Added Debian package support (specifically Ubuntu package support).
   179   * Added missing COPYING.txt file.
   180   * Renamed the scripts to avoid naming issues in system-wide installations.
   181   * Added a PyQt example based on the system configurator example, with the
   182     form prepared in Qt Designer. This example runs in PyQt and in a Web
   183     environment without any changes to the application code. In-page updates
   184     are currently not implemented in the Web version, however.
   185 
   186 Notes on In-Page Update Functionality
   187 -------------------------------------
   188 
   189 Special note #1: Konqueror seems in certain cases to remember replaced form
   190 content (when replaceChild is used to replace regions of the page which
   191 include form elements). This causes the browser to believe that more form
   192 fields exist on the page than actually do so, and subsequent form submissions
   193 thus include the values of such removed fields. A special hack is in place to
   194 disable form fields by changing their names, thus causing Konqueror to not
   195 associate such fields with the real, active fields; this hack does not seem to
   196 cause problems for Mozilla. This needs some investigation to determine in
   197 exactly which circumstances the problem arises.
   198 
   199 Special note #2: Konqueror also seems to crash if asked to find elements using
   200 an empty 'id' attribute string. This needs some investigation to see if it
   201 really is the getElementById call that causes the crash.
   202 
   203 Special note #3: Konqueror's XMLHttpRequest seems to append null characters to
   204 the end of field values. Attempting to prune them before the request is sent
   205 fails with a function like the following:
   206 
   207 function fixValue(fieldValue) {
   208     if (fieldValue.length == 0) {
   209         return fieldValue;
   210     } else if (fieldValue[fieldValue.length - 1] == '\0') {
   211         return fieldValue.substr(0, fieldValue.length - 1);
   212     } else {
   213         return fieldValue;
   214     }
   215 }
   216 
   217 This may be because it is the entire message that is terminated with the null
   218 character, and that this happens only upon sending the message. Consequently,
   219 some frameworks (notably mod_python) do not support in-page functionality when
   220 used from Konqueror.
   221 
   222 Various browsers (eg. Mozilla/Firefox, Konqueror) will not allow the
   223 XMLHttpRequest in-page updates to function unless the URL used in the
   224 requestUpdate JavaScript function is compatible with the URL at which the
   225 browser finds the application. Currently, relative URLs are in use to avoid
   226 this issue of compatibility, but should an absolute URL be deduced using the
   227 WebStack API and then used, it may be possible that the values returned by
   228 that API do not match the actual addresses entered into the address bar of the
   229 browser.
   230 
   231 To check the behaviour of the applications, it is possible to view the
   232 document source of the pages served by applications and to verify that the
   233 URLs mentioned in the JavaScript function calls (to 'requestUpdate') either be
   234 a relative link or involve a URL similar to that which appears in the
   235 browser's address bar. In some environments, the use of 'localhost' addresses
   236 often confuses the browser and server; one workaround is to use real host
   237 names or addresses instead of 'localhost'.
   238 
   239 Choosing an element-path:
   240 
   241 When specifying the "context" of the in-page update, one must imagine which
   242 element the template fragment should operate within. If the template:id
   243 attribute marks a particular section, then the element-path should be a path
   244 to the applicable context element for that section in the complete template
   245 document. Note that if a template:element attribute appears on the same
   246 element as the template:id attribute then the element-path should refer to the
   247 element specified in the template:element attribute.
   248 
   249 Choosing where to put template:attribute, template:id and id:
   250 
   251 When specifying the extent of a template fragment, one must be sure not to put
   252 the template:id attribute on the same element as a template:attribute
   253 annotation; otherwise, the generated code will be improperly extracted as a
   254 fragment producing two versions of the element - one for when the specified
   255 attribute is present, and one for when it is not present. Generally,
   256 template:id and id can be placed on the same node, however.
   257 
   258 Stable element ordering and element-path:
   259 
   260 Within the element-path, the numbering of the elements will start at 1.
   261 Therefore it is vital to choose a region of the form data structure with the
   262 element-path which is isolated from surrounding elements whose positions would
   263 otherwise be dependent on a stable ordering of elements, and whose processing
   264 would be disrupted if some new elements suddenly appeared claiming the same
   265 positions in the document. For example:
   266 
   267   <item value="">         .../item$1/value
   268     <type value=""/>      .../item$1/type$1/value
   269     <comment value=""/>   .../item$1/comment$2/value
   270   </item>
   271 
   272   In-page update...
   273 
   274   <comment value=""/>     .../item$1/comment$1/value
   275 
   276 Notes on XSL
   277 ------------
   278 
   279 libxslt seems to be quite liberal on the definition of runtime parameters, in
   280 that there is no apparent need to explicitly declare the corresponding global
   281 variables in stylesheets. Whilst this is nice, we may eventually need to
   282 detect such variables and add them in the preparation process.
   283 
   284 Release Procedures
   285 ------------------
   286 
   287 Update the XSLTools/__init__.py and XSLForms/__init__.py __version__
   288 attributes.
   289 Change the version number and package filename/directory in the documentation.
   290 Change code examples in the documentation if appropriate.
   291 Update the release notes (see above).
   292 Check the setup.py file and ensure that all package directories are mentioned.
   293 Check the release information in the PKG-INFO file and in the package
   294 changelog (and other files).
   295 Tag, export.
   296 Generate the example resources.
   297 Generate the API documentation.
   298 Remove generated .pyc files: rm `find . -name "*.pyc"`
   299 Archive, upload.
   300 Upload the introductory documentation.
   301 Update PyPI, PythonInfo Wiki, Vaults of Parnassus entries.
   302 
   303 Generating the Example Resources
   304 --------------------------------
   305 
   306 In order to prepare the example resources, the prepare_demo.py script must be
   307 run as follows:
   308 
   309 python tools/prepare_demo.py
   310 
   311 This will ensure that all initialiser and output stylesheets are created and
   312 are thus installed by packages.
   313 
   314 Generating the API Documentation
   315 --------------------------------
   316 
   317 In order to prepare the API documentation, it is necessary to generate some
   318 Web pages from the Python source code. For this, the epydoc application must
   319 be available on your system. Then, inside the distribution directory, run the
   320 apidocs.sh tool script as follows:
   321 
   322 ./tools/apidocs.sh
   323 
   324 Some warnings may be generated by the script, but the result should be a new
   325 apidocs directory within the distribution directory.
   326 
   327 Making Packages
   328 ---------------
   329 
   330 To make Debian-based packages:
   331 
   332   1. Create new package directories under packages if necessary.
   333   2. Make a symbolic link in the distribution's root directory to keep the
   334      Debian tools happy:
   335 
   336      ln -s packages/ubuntu-hoary/python2.4-xsltools/debian/
   337 
   338   3. Run the package builder:
   339 
   340      dpkg-buildpackage -rfakeroot
   341 
   342   4. Locate and tidy up the packages in the parent directory of the
   343      distribution's root directory.