Difference between revisions of "SMILA/Documentation/Importing/Crawler/File"

Revision as of 05:34, 21 May 2012

Currently, the file system workers are implemented very simplistic so that we can test the importing framework. A sophisticated implementation will follow soon.

File Crawler

The File Crawler imports files from a root folder and all subdirectories below.

Configuration

The File Crawler worker is usually the first worker in a workflow and the job is started in runOnce mode.

• Worker name: fileCrawler
• Parameters:
  • dataSource: (req.) value for attribute _source, needed by the delta service
  • rootFolder: (req.) crawl starting point
  • filters (opt.) filters with conditions to in- or exclude files and folders from import
    • maxFileSize: maximum file size, files that are bigger are filtered out
    • maxFolderDepth: starting from the root folder, this is the maximum depth to crawl into subdirectories
    • followSymbolicLinks: whether to follow symbolic links to files/folders or not
    • filePatterns: regex patterns for filtering crawled files on the basis of their file name
      • include: if include patterns are specified, at least one of them must match the file name. If no include patterns are specified, this is handled as if all file names are included.
      • exclude: if at least one exclude pattern matches the file name, the crawled file is filtered out
    • folderPatterns: regex patterns for filtering crawled folders and files on the basis of their file path
      • include: Only relevant for crawled files: If include patterns are specified, at least one of them must match the file path. If no include patterns are specified, this is handled as if all file paths are included.
      • exclude: Only relevant for crawled folders: If at least one exclude pattern matches the folder name, the folder (and its subdirectories) will not be crawled.
  • mapping (req.) specifies how to map file properties to record attributes
    • filePath (opt.) mapping attribute for the complete file path
    • fileFolder (opt.) mapping attribute for the file folder
    • fileName (opt.) mapping attribute for the file name
    • fileExtension (opt.) mapping attribute for the file extension
    • fileSize (opt.) mapping attribute for the file size (in bytes)
    • fileLastModified (opt.) mapping attribute for the file's last modified date
    • fileContent (opt.) mapping attribute for the file's last modified date
• Task generator: runOnceTrigger
• Input slots:
  • directoriesToCrawl
• Output slots:
  • directoriesToCrawl
  • filesToCrawl

Processing

The File Crawler starts crawling in the rootFolder and produces one record for each subdirectory in the bucket connected to directoriesToCrawl (and each record goes to an own bulk), and one record per file in the folder in bucket connected to filesToCrawl (a new bulk is started each 1000 files). The bucket in slot directoriesToCrawl should be connected to the input slot of the File Crawler so that the subdirectories are crawled in followup tasks. The file records do not yet contain the file content but only metadata attributes:

• fileName
• fileFolder
• filePath (also set as record ID)
• fileExtension
• fileSize
• fileLastModified (also written to attribute _deltaHash for delta checking)

The attribute _source is set from the task parameter dataSource which has no further meaning currently, but it is needed by the delta service.

Compounds

If the runnning CompoundExtractor service identifies an object as a extractable compound, it is marked with attribute _isCompound set to true.

• Dependency: CompoundExtractor service

Examples

Example of a file crawl job:

 {
   "name":"crawlFileJob",
   "workflow":"fileCrawling",
   "parameters":{
     "tempStore":"temp",
     "dataSource":"files",
     "rootFolder":"/temp",
     "jobToPushTo":"buildBulks",
     "mapping":{
       "fileContent":"fileContent",
       "filePath":"filePath",
       "fileFolder":"fileFolder",
       "fileName":"fileName",
       "fileSize":"fileSize",
       "fileExtension":"fileExtension",
       "fileLastModified":"fileLastModified"
     },
     "filters":{
       "maxFileSize":1000000000,
       "maxFolderDepth":10,
       "followSymbolicLinks":true,
       "filePatterns":{
         "include":[".*"],
         "exclude":["invalid.txt", "invalid.pdf"]  
       },          
       "folderPatterns":{
         "include":[".*"],
         "exclude":["invalid-dir"]  
       }
     }
   }
 }

File Fetcher

• Worker name: fileCrawler
• Parameters: none
• Input slots:
  • filesToFetch

• Output slots:
  • files

For each input record, reads the file referenced in attribute filePath and adds the content as attachment fileContent

File Extractor Worker

• Worker name: fileExtractor
• Parameters: none
• Input slots:
  • compounds
• Output slots:
  • files

• Dependency: CompoundExtractor service

For each input record, an input stream to the described file is created and fed into the CompoundExtractor service. The produced records are converted to look like records produced by the file crawler, with these attributes set (if provided by the extractor):

• filePath: complete path in compound
• fileFolder: folder of element in compound
• fileName: filename part of path
• fileExtension: extension part of filename
• fileLastModified: last modification timestamp
• fileSize: uncompressed size
• _deltaHash: computed as by the FileCrawler worker
• _compoundRecordId: record ID of top-level compound this element was extracted from
• _isCompound: set to true for elements that are compounds themselves.
• _compoundPath: sequence of filePath attribute values of the compound objects needed to navigate to the compound element.

If the element is not a compound itself, its content is added as attachment fileContent.