Package freemarker.cache

Class FileTemplateLoader

  • All Implemented Interfaces:
    SecureTemplateLoader, TemplateLoader
    public class FileTemplateLoader
extends Object
implements SecureTemplateLoader
    A TemplateLoader that uses files in a specified directory as the source of templates. If contains security checks that will prevent it serving templates outside the template directory (like <include /etc/passwd>. It compares canonical paths for this, so templates that are symbolically linked into the template directory from outside of it won't work either. The code source URL of the templates can be either globally set to the base directory, or if more fine-grained access control is required, then each template can have a code source URL of its file.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      File baseDir
      The base directory used as the root of the namespace for resolving template paths.

    • Constructor Summary

      Constructors 
      Constructor Description
      FileTemplateLoader()
      Creates a new file template cache that will use the current directory (the value of the system property user.dir as the base directory for loading templates.
      FileTemplateLoader​(File baseDir)
      Creates a new file template loader that will use the specified directory as the base directory for loading templates.
      FileTemplateLoader​(File baseDir, boolean allowLinking)
      Creates a new file template loader that will use the specified directory as the base directory for loading templates and a specified code source policy.
      FileTemplateLoader​(File baseDir, boolean allowLinking, boolean useBaseDirCodeSource)
      Creates a new file template loader that will use the specified directory as the base directory for loading templates and a specified code source policy.

    • Field Detail

      • baseDir

        public final File baseDir
        The base directory used as the root of the namespace for resolving template paths.

    • Constructor Detail

      • FileTemplateLoader

        public FileTemplateLoader()
                   throws IOException
        Creates a new file template cache that will use the current directory (the value of the system property user.dir as the base directory for loading templates. The code source URL of all templates will be set to the directory, so a single set of permissions that applies to the directory will apply to all templates.
        Throws:
        IOException - if an I/O exception occurs

      • FileTemplateLoader

        public FileTemplateLoader​(File baseDir)
                   throws IOException
        Creates a new file template loader that will use the specified directory as the base directory for loading templates. The code source URL of all templates will be set to the directory, so a single set of permissions that applies to the directory will apply to all templates.
        Parameters:
        baseDir - the base directory for loading templates
        Throws:
        IOException - if an I/O exception occurs

      • FileTemplateLoader

        public FileTemplateLoader​(File baseDir,
                          boolean allowLinking)
                   throws IOException
        Creates a new file template loader that will use the specified directory as the base directory for loading templates and a specified code source policy.
        Parameters:
        baseDir - the base directory for loading templates
        allowLinking - if true, it will allow following symlinks pointing outside the baseDir
        Throws:
        IOException - if an I/O exception occurs

      • FileTemplateLoader

        public FileTemplateLoader​(File baseDir,
                          boolean allowLinking,
                          boolean useBaseDirCodeSource)
                   throws IOException
        Creates a new file template loader that will use the specified directory as the base directory for loading templates and a specified code source policy.
        Parameters:
        baseDir - the base directory for loading templates
        allowLinking - if true, it will allow following symlinks pointing outside the baseDir
        useBaseDirCodeSource - if true, the code source URL of all templates will be set to the file: URL of the directory, so a single set of permissions that applies to the directory will apply to all templates. If false, the code source URL of each template will be the file: URL of that template, so a finer-grained access control can be specified in the policy file at expense of having multiple code sources.
        Throws:
        IOException - if an I/O exception occurs

    • Method Detail

      • findTemplateSource

        public Object findTemplateSource​(String name)
                          throws IOException
        Description copied from interface: TemplateLoader
        Finds the object that acts as the source of the template with the given name. This method is called by the TemplateCache when a template is requested, before calling either TemplateLoader.getLastModified(Object) or TemplateLoader.getReader(Object, String).
        Specified by:
        findTemplateSource in interface TemplateLoader
        Parameters:
        name - the name of the template, already localized and normalized by the cache. It is completely up to the loader implementation to interpret the name, however it should expect to receive hierarchical paths where path components are separated by a slash (not backslash). Backslashes (or any other OS specific separator character) are not considered as separators by FreeMarker, and thus they will not be replaced with slash before passing to this method, so it is up to the template loader to handle them (say, be throwing and exception that tells the user that the path (s)he has entered is invalid, as (s)he must use slash -- typical mistake of Windows users). The passed names are always considered relative to some loader-defined root location (often reffered as the "template root direcotry"), and will never start with a slash, nor will they contain a path component consisting of either a single or a double dot -- these are all resolved by the template cache before passing the name to the loader. As a side effect, paths that trivially reach outside template root directory, such as ../my.ftl, will be rejected by the template cache, so they never reach the template loader. Note again, that if the path uses backslash as path separator instead of slash as (the template loader should not accept that), the normalisation will not properly happen, as FreeMarker (the cache) recognizes only the slashes as separators.
        Returns:
        an object representing the template source, which can be supplied in subsequent calls to TemplateLoader.getLastModified(Object) and TemplateLoader.getReader(Object, String). Null must be returned if the source for the template can not be found (do not throw FileNotFoundException!). The returned object may will be compared with a cached template source object for equality, using the equals method. Thus, objects returned for the same physical source must be equivalent according to equals method, otherwise template caching can become very ineffective!
        Throws:
        IOException - if there is an I/O exception while looking for the template source

      • getLastModified

        public long getLastModified​(Object templateSource)
        Description copied from interface: TemplateLoader
        Returns the time of last modification of the specified template source. This method is called after findTemplateSource().
        Specified by:
        getLastModified in interface TemplateLoader
        Parameters:
        templateSource - an object representing a template source, obtained through a prior call to TemplateLoader.findTemplateSource(String).
        Returns:
        the time of last modification of the specified template source, or -1 if the time is not known.

      • getReader

        public Reader getReader​(Object templateSource,
                        String encoding)
                 throws IOException
        Description copied from interface: TemplateLoader
        Returns the character stream of a template represented by the specified template source. This method is called after getLastModified() if it is determined that a cached copy of the template is unavailable or stale.
        Specified by:
        getReader in interface TemplateLoader
        Parameters:
        templateSource - an object representing a template source, obtained through a prior call to TemplateLoader.findTemplateSource(String).
        encoding - the character encoding used to translate source bytes to characters. Some loaders may not have access to the byte representation of the template stream, and instead directly obtain a character stream. These loaders will - quite naturally - ignore the encoding parameter.
        Returns:
        a reader representing the template character stream. The framework will call close().
        Throws:
        IOException - if an I/O error occurs while accessing the stream.

      • closeTemplateSource

        public void closeTemplateSource​(Object templateSource)
        Description copied from interface: TemplateLoader
        Closes the template source. This is the last method that is called by the TemplateCache for a templateSource. The framework guarantees that this method will be called on every object that is returned from TemplateLoader.findTemplateSource(String).
        Specified by:
        closeTemplateSource in interface TemplateLoader
        Parameters:
        templateSource - the template source that should be closed.

      • getCodeSource

        public CodeSource getCodeSource​(Object templateSource)
                         throws IOException
        Description copied from interface: SecureTemplateLoader
        Returns a code source for a template source.
        Specified by:
        getCodeSource in interface SecureTemplateLoader
        Parameters:
        templateSource - the template source for which a code source is requested.
        Returns:
        the code source for the specified template source, or null if it can not be obtained
        Throws:
        IOException - if an I/O exception occurs while trying to obtain the code source.