2.18. 元数据和著作人信息

由某个实现所提供的非必需、不影响正确执行的扩展（如关于图形界面中展示的字段），以及关于工具或工作流本身的元数据（如用于引文的作者信息），都可以作为任意对象的附加字段提供。这种扩展字段（形如 format: edam:format_2572）可以使用文件 $namespaces（命名空间）部分依照 Schema Salad 规约的要求列举的命名空间前缀（例如 edam：http://edamontology.org/）。如下所示，一旦添加了命名空间前缀，便可在文档的任何位置使用它。否则，必须使用完整的 URL: format: http://edamontology.org/format_2572.

我们建议所有的开发者为自己编写的工具和工作流提供类似下面所示的精简版元数据。此例中的元数据向他人说明如何在文献中引用你的工具。

metadata_example2.cwl

#!/usr/bin/env cwl-runner
cwlVersion: v1.2
class: CommandLineTool

label: An example tool demonstrating metadata.
doc: Note that this is an example and the metadata is not necessarily consistent.

inputs:
  aligned_sequences:
    type: File
    label: Aligned sequences in BAM format
    format: edam:format_2572
    inputBinding:
      position: 1

baseCommand: [ wc, -l ]

stdout: output.txt

outputs:
  report:
    type: stdout
    format: edam:format_1964
    label: A text file that contains a line count

s:author:
  - class: s:Person
    s:identifier: https://orcid.org/0000-0002-6130-1021
    s:email: mailto:dyuen@oicr.on.ca
    s:name: Denis Yuen

s:contributor:
  - class: s:Person
    s:identifier: http://orcid.org/0000-0002-7681-6415
    s:email: mailto:briandoconnor@gmail.com
    s:name: Brian O'Connor

s:citation: https://dx.doi.org/10.6084/m9.figshare.3115156.v2
s:codeRepository: https://github.com/common-workflow-language/common-workflow-language
s:dateCreated: "2016-12-13"
s:license: https://spdx.org/licenses/Apache-2.0

$namespaces:
  s: https://schema.org/
  edam: http://edamontology.org/

$schemas:
  - https://schema.org/version/latest/schemaorg-current-https.rdf
  - http://edamontology.org/EDAM_1.18.owl

这一 CWL 描述的等效命令行形式为：

$ wc -l /path/to/aligned_sequences.ext > output.txt

2.18.1. 进一步扩展的例子

如果您积极性更高，也可以加入更多的元数据来注释工具。此例中加入了 EDAM 本体标签作为关键字（以便将彼此关联的工具分组）、关于硬件要求的软性提示，以及其他元数据字段。

metadata_example3.cwl

#!/usr/bin/env cwl-runner
cwlVersion: v1.2
class: CommandLineTool

label: An example tool demonstrating metadata.
doc: Note that this is an example and the metadata is not necessarily consistent.

hints:
  ResourceRequirement:
    coresMin: 4

inputs:
  aligned_sequences:
    type: File
    label: Aligned sequences in BAM format
    format: edam:format_2572
    inputBinding:
      position: 1

baseCommand: [ wc, -l ]

stdout: output.txt

outputs:
  report:
    type: stdout
    format: edam:format_1964
    label: A text file that contains a line count

s:author:
  - class: s:Person
    s:identifier: https://orcid.org/0000-0002-6130-1021
    s:email: mailto:dyuen@oicr.on.ca
    s:name: Denis Yuen

s:contributor:
  - class: s:Person
    s:identifier: http://orcid.org/0000-0002-7681-6415
    s:email: mailto:briandoconnor@gmail.com
    s:name: Brian O'Connor

s:citation: https://dx.doi.org/10.6084/m9.figshare.3115156.v2
s:codeRepository: https://github.com/common-workflow-language/common-workflow-language
s:dateCreated: "2016-12-13"
s:license: https://spdx.org/licenses/Apache-2.0

s:keywords: edam:topic_0091 , edam:topic_0622
s:programmingLanguage: C

$namespaces:
  s: https://schema.org/
  edam: http://edamontology.org/

$schemas:
  - https://schema.org/version/latest/schemaorg-current-https.rdf
  - http://edamontology.org/EDAM_1.18.owl