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MapServer 4.10 to 5.0 Migration Guide
This page documents the changes that must be made to MapServer applications when migrating from version 4.10.x (or earlier versions) to 5.x (i.e. backwards incompatibilities), as well as information on some of the new features.
Attribute Bindings: In an effort to stem the tide of keyword overload and add functionality MapServer 5.0 supports a new method of binding feature attributes to STYLE and LABEL properties. In the past keywords like ANGLEITEM or LABELSIZEITEM were used, now you denote the attribute in the context of the property being bound. For example, to bind an attribute to a label size you'd do:
LABEL ... SIZE [mySizeItem] END
The 's denote a binding (as with logical expressions). The following keywords are no longer supported and their presence will throw an error:
- Layer: LABELANGLEITEM, LABELSIZEITEM
- Style: ANGLEITEM, SIZEITEM
The following properties can accept bindings:
- Style: angle, color, outlinecolor, size, symbol
- Label: angle, color, outlinecolor, size, font, priority
Colors may be given as a hex value (e.g. #FFFFFF) or an RGB triplet (e.g. 255 255 255).
Layer Transparency: The values for the TRANSPARENCY parameter have always been backwards and in an effort to resolve that the parameter has been renamed OPACITY. TRANSPARENCY is still recognized by the mapfile parser but is depricated and should be avoided.
Scale Parameters: MapServer's handling of scale has long been a source for confusion. The values use in a layer MINSCALE are really the denominators from a representative fraction (e.g. 1:24000). To help clarify this all scale parameters are now end with DENOM. So MINSCALE => MINSCALEDENOM, SYMBOLSCALE => SYMBOLSCALEDENOM, and so on. The mapfile parser still recognizes the older keywords but they are depricated and should be avoided.
Symbol file changes
Symbol Style: STYLEs are used within a symbol definition to store dash patterns for line symbolization. However, there is potential confusion with the style object that is used within class definitions. To resolve that confusion the symbol STYLE parameter has been renamed PATTERN. The symbol file parser will still recognize the STYLE keyword but it is depricated and should be avoided.
Prior to MapsServer 5.0, if a pixmap symbol was used in style on a Line Layer, the symbol was used as a brush to draw the line. In MapServer 5.0, it is possible to draw the pixmap symbol along the line (Note that this was available using a true type symbol). To achieve this, the user needs to use the parameter GAP with it's pixmap symbol definition in the symbol file. The GAP represents the distance between the symbols. If the GAP is not given, the pixmap symbol will be used as a brush.
AGG rendering changes
URL configuration changes
Previous versions of the MapServer CGI program allowed certain parameters to be changed via a URL using a cumbersome syntax such as map_layer_0_class_0_color=255+0+0 which changes the color in one classObj. Not only was this cumbersome for users but also from a code maintenance perspective since we had to maintain seperate loaders for URL-based config and file-based config. RFC-31 attempts to streamline both by migrating to a single object loading function that can be used with strings (either in MapScript or via URL) or with files.
So, in the past you have to change parameters one-at-a-time. Now you can pass chunks of mapfiles (with security restrictions) to the CGI interface. The map_object notation is still necessary to identify which object you want to modify but you can change multiple properties at one time. Note that you can use either a '_' or a '.' to seperate identifiers.
Example 1, changing a scalebar object:
Example 2, changing a presentation style:
Example 3, creating a new feature
The variable identifies an object uniquely (by name or index in the case of layerObj's and classObj's). The value is a snippet of a mapfile. You cannot create new objects other than inline features at this point.
Validation patterns for mapserv attribute queries
Attribute queries (qstring) done via the mapserv CGI could theoretically be used for SQL injection.
No exploit has been reported, but in order to mitigate the risk, a new validation pattern mechanism has been added in 5.0.
In the case of qstring attribute queries, the qstring_validation_pattern layer-level metadata is required for qstring queries to work. The metadata value is a regular expression that the qstring value must match otherwise mapserv produces a fatal error. A fatal error is also produced if qstring is used but qstring_validation_pattern is not provided.
Note that similar validation pattern mechanism has been available for %variable% substitutions since version 4.10, but in this case it is optional. The pattern for %myvar% is provided via a metadata called myvar_validation_pattern.
SWIG MapScript (Python, Perl, CSharp, Java) changes
Layer Transparency: The layerObj transparency parameter is now called opacity. Scripts setting that value in code must be updated.
Symbol Style: the symbolObj style parameter is now called pattern. MapScript does not allow direct modification of that parameter. In Swig-based languages the symbolObj method setStyle is now called setPattern. In PHP/MapScript, the methods setStyle and getStyle are now called setPattern and getPattern.
A new msGetVersionInt() function returning the current MapServer version in integer format has been added to facilitate version checks in the future. Given version x.y.z, it returns (x*0x10000 + y*0x100 + z). For instance, for v5.0.0 it will return 0x050000 (note the hexadecimal notation).
Layer Transparency: The layerObj transparency parameter is now called opacity. The old "transparency" name is deprecated and will be removed in a future release. Scripts getting/setting that value in code must be updated.
All occurences of scale, minscale, maxscale, etc... parameters have been deprecated and renamed with a "denom" suffix (e.g. minscale becomes minscaledenom, etc.). The deprecated parameters will be removed in a future release. Scripts getting/setting them must be updated.
SymbolObj style has been renamed pattern. The old "stylelength" parameter and setStyle() and getStyleArray() methods have been deprecated and "patternlength", setPattern() and getPatternArray() should be used instead. They will be removed in a future release.
layer.getShape(int tileindex, int shapeindex)) has been deprecated and renamed to layer.getFeature(int shapeindex [, int tileindex = -1]) to match the SWIG MapScript equivalent. Note that the order of the arguments is reversed since tileindex is optional in getFeature().
class.getExpression() and layer.getFilter() have been deprecated and renamed to class.getExpressionString() and layer.getFilterString() to match what we have in SWIG MapScript. The String suffix in the function name also more clearly indicates that the return value is not an object but a string representation of it.
A new ms_GetVersionInt() function returning the current MapServer version in integer format has been added to facilitate version checks in the future. Given version x.y.z, it returns (x*0x10000 + y*0x100 + z). For instance, for v5.0.0 it will return 0x050000 (note the hexadecimal notation).
OGC Web Map Service (WMS)
Required Parameters for GetMap and GetFeatureInfo: previously, MapServer did not check for the following parameters when responding to an OGC:WMS GetMap or GetFeatureInfo request:
- STYLES or SLD / SLD_BODY
That is, a GetMap request would process without error if these were not passed by the WMS client.
A compliant OGC:WMS 1.1.0 and 1.1.1 REQUIRES these parameters. This may affect OGC:WMS client requests who were not passing these values. Ticket 1088 fully documents this issue. In addition to WMS compliance, this was also decided that by adding this constraint, if an OGC client request (as described earlier) breaks something, people should fix their client anyway since if they change WMS vendor, they will have problems as well.
OGC Web Feature Service (WFS)
MapServer's main include file has been renamed from "map.h" to "mapserver.h".
A new mapserver-config script has been created with the following options:
Usage: mapserver-config [OPTIONS] Options: [--libs] [--dep-libs] [--cflags] [--defines] [--includes] [--version]
The shared and static link libraries for MapSserver have been renamed libmapserver.x.y.so and libmapserver.a respectively.
The --enable-coverage configure option has been renamed to --enable-gcov since the former name led users to think it might be related to enabling support for WCS or Arc/Info coverages:
--enable-gcov Enable source code coverage testing using gcov
Features Heading for Deprecation
Some features present in MapServer are likely to be removed in a future release. Features might be headed for deprecation because:
- they have been replaced by a superior or more capable solution
- they have stopped being maintained
Users of these features should be prepared for these upcoming changes and start adapting their mapfiles in consequence. If you have strong and motivated objections as to the removal of one or more of these features please open a discussion in the usual Mapserver communication channels.
Cartoline symbols: these were a hack to overcome GD weaknesses, and their functionality is now supported by the AGG renderer. They have become poorly supported in current MapServer versions. Keywords allowing for setting the style of line joins and caps will be moved to the STYLE block.
RGB/RGBA output with GD: support for RGB and RGBA image types will likely not be maintained anymore. PC256 will continue to be supported with GD, while RGB and RGBA will liekly only be supported with AGG