服务任务

服务任务从 HTTP 服务提取内容。

示例

以下展示了将此任务作为工作流一部分的简单示例。

from txtai.workflow import ServiceTask, Workflow

workflow = Workflow([ServiceTask(url="https://service.url/action)])
workflow(["parameter"])

配置驱动的示例

此任务也可以通过工作流配置创建。

workflow:
  tasks:
    - task: service
      url: https://service.url/action

方法

此任务的 Python 文档。

__init__(action=None, select=None, unpack=True, column=None, merge='hstack', initialize=None, finalize=None, concurrency=None, onetomany=True, **kwargs)

创建一个新任务。任务定义了两个方法、接受的数据类型以及对每个数据元素执行的操作。操作可以是可调用函数或可调用函数列表。

参数

名称	类型	描述	默认值
action		对每个数据元素执行的操作	None
select		用于选择要处理数据的过滤器	None
unpack		是否应从 (id, data, tag) 元组中解包或展开数据元素	True
column		如果元素是元组，要选择的列索引，默认为全部	None
merge		用于连接多操作输出的合并模式，默认为 hstack	'hstack'
initialize		处理前执行的操作	None
finalize		处理后执行的操作	None
concurrency		设置执行实例可用时的并发方法，有效值："thread" 表示基于线程的并发，"process" 表示基于进程的并发	None
onetomany		是否启用一对多数据转换，默认为 True	True
kwargs		附加关键字参数	{}

源代码位于 txtai/workflow/task/base.py

def __init__(
    self,
    action=None,
    select=None,
    unpack=True,
    column=None,
    merge="hstack",
    initialize=None,
    finalize=None,
    concurrency=None,
    onetomany=True,
    **kwargs,
):
    """
    Creates a new task. A task defines two methods, type of data it accepts and the action to execute
    for each data element. Action is a callable function or list of callable functions.

    Args:
        action: action(s) to execute on each data element
        select: filter(s) used to select data to process
        unpack: if data elements should be unpacked or unwrapped from (id, data, tag) tuples
        column: column index to select if element is a tuple, defaults to all
        merge: merge mode for joining multi-action outputs, defaults to hstack
        initialize: action to execute before processing
        finalize: action to execute after processing
        concurrency: sets concurrency method when execute instance available
                     valid values: "thread" for thread-based concurrency, "process" for process-based concurrency
        onetomany: if one-to-many data transformations should be enabled, defaults to True
        kwargs: additional keyword arguments
    """

    # Standardize into list of actions
    if not action:
        action = []
    elif not isinstance(action, list):
        action = [action]

    self.action = action
    self.select = select
    self.unpack = unpack
    self.column = column
    self.merge = merge
    self.initialize = initialize
    self.finalize = finalize
    self.concurrency = concurrency
    self.onetomany = onetomany

    # Check for custom registration. Adds additional instance members and validates required dependencies available.
    if hasattr(self, "register"):
        self.register(**kwargs)
    elif kwargs:
        # Raise error if additional keyword arguments passed in without register method
        kwargs = ", ".join(f"'{kw}'" for kw in kwargs)
        raise TypeError(f"__init__() got unexpected keyword arguments: {kwargs}")

register(url=None, method=None, params=None, batch=True, extract=None)

将服务参数添加到任务。检查是否已安装所需的依赖项。

参数

名称	类型	描述	默认值
url		要连接的 url	None
method		http 方法，GET 或 POST	None
params		默认查询参数	None
batch		如果为 True，所有元素都在单个批量请求中传递，否则对每个元素执行一次服务调用	True
extract		从响应中提取的 sections 列表	None

源代码位于 txtai/workflow/task/service.py

def register(self, url=None, method=None, params=None, batch=True, extract=None):
    """
    Adds service parameters to task. Checks if required dependencies are installed.

    Args:
        url: url to connect to
        method: http method, GET or POST
        params: default query parameters
        batch: if True, all elements are passed in a single batch request, otherwise a service call is executed per element
        extract: list of sections to extract from response
    """

    if not XML_TO_DICT:
        raise ImportError('ServiceTask is not available - install "workflow" extra to enable')

    # pylint: disable=W0201
    # Save URL, method and parameter defaults
    self.url = url
    self.method = method
    self.params = params

    # If True, all elements are passed in a single batch request, otherwise a service call is executed per element
    self.batch = batch

    # Save sections to extract. Supports both a single string and a hierarchical list of sections.
    self.extract = extract
    if self.extract:
        self.extract = [self.extract] if isinstance(self.extract, str) else self.extract