【已解决】Flask-Restful中如何设计分页的API

Returns per_page items from page page. By default it will abort with 404 if no items were found and the page was larger than 1. This behavor can be disabled by setting error_out to False.

If page or per_page are None, they will be retrieved from the request query. If the values are not ints and error_out is true, it will abort with 404. If there is no request or they aren’t in the query, they default to page 1 and 20 respectively.

Returns an Pagination object.

Utilities

class flask.ext.sqlalchemy.Pagination(query, page, per_page, total, items)

Internal helper class returned by BaseQuery.paginate(). You can also construct it from any other SQLAlchemy query object if you are working with other libraries. Additionally it is possible to pass None as query object in which case the prev() and next() will no longer work.

has_next

True if a next page exists.

has_prev

True if a previous page exists

items = None

the items for the current page

iter_pages(left_edge=2, left_current=2, right_current=5, right_edge=2)

Iterates over the page numbers in the pagination. The four parameters control the thresholds how many numbers should be produced from the sides. Skipped page numbers are represented as None. This is how you could render such a pagination in the templates:

{% macro render_pagination(pagination, endpoint) %}

{%- for page in pagination.iter_pages() %}

{% if page %}

{% if page != pagination.page %}

{% else %}

{% endif %}

{% else %}

{% endif %}

{%- endfor %}

</div>

{% endmacro %}

next(error_out=False)

Returns a Pagination object for the next page.

next_num

Number of the next page

page = None

the current page number (1 indexed)

pages

The total number of pages

per_page = None

the number of items to be displayed on a page.

prev(error_out=False)

Returns a Pagination object for the previous page.

prev_num

Number of the previous page.

query = None

the unlimited query object that was used to create this pagination object.

total = None

the total number of items matching the query

[AF][Flask-SQLAlchemy] Pagination：flask

【总结】

然后此处，参考了：

API — Flask-SQLAlchemy Documentation (2.1)

最后写成：

<code>
        curPageTaskList = None

        # for debug
        taskPagination = None

        if curRole == UserRole.Initiator:
            taskPagination = Task.query.filter_by(initiatorId=userId).paginate(
                page=curPageNum,
                per_page=numPerPage,
                error_out=False)
        elif curRole == UserRole.Errandor:
            taskPagination = Task.query.filter_by(errandorId=userId).paginate(
                page=curPageNum,
                per_page=numPerPage,
                error_out=False)

        gLog.debug("type(taskPagination)=%s"
                   ",taskPagination=%s"
                   ",has_next=%s"
                   ",has_prev=%s"
                   # ",items=%s"
                   # ",next()=%s"
                   # ",next_num=%s"
                   ",page=%s"
                   ",pages=%s"
                   ",per_page=%s"
                   # ",prev_num=%s"
                   # ",query=%s"
                   ",total=%s",
                   type(taskPagination),
                   taskPagination,
                   taskPagination.has_next,
                   taskPagination.has_prev,
                   # taskPagination.items,
                   # taskPagination.next(error_out=False),
                   # taskPagination.next_num,
                   taskPagination.page,
                   taskPagination.pages,
                   taskPagination.per_page,
                   # taskPagination.prev_num,
                   # taskPagination.query,
                   taskPagination.total
                   )

        # gLog.debug("type(taskPagination)=%s,taskPagination=%s", type(taskPagination), taskPagination)
        # type(taskPagination)=&lt;class 'flask_sqlalchemy.Pagination'&gt;, taskPagination=&lt;flask_sqlalchemy.Pagination object at 0x7f07b83c7950&gt;

        paginatedTaskList = taskPagination.items
        # gLog.debug("type(paginatedTaskList)=%s, paginatedTaskList=%s", type(paginatedTaskList), paginatedTaskList)

        paginatedTaskDict = {}
        for curIdx, eachTask in enumerate(paginatedTaskList):
            # gLog.debug("[%s] eachTask=%s", curIdx, eachTask)
            gLog.debug("[%s] eachTask.id=%s", curIdx, eachTask.id)
            paginatedTaskDict[eachTask.id] = marshal(eachTask, task_fields)

        respPaginatedTaskInfoDict = {
            "curPageNum"    : taskPagination.page,
            "totalPageNum"  : taskPagination.pages,
            "numPerPage"    : taskPagination.per_page,
            "hasPrev"       : taskPagination.has_prev,
            "hasNext"       : taskPagination.has_next,
            "totalTaskNum"  : taskPagination.total,
            'tasks'         : paginatedTaskDict
        }

        gLog.debug("respPaginatedTaskInfoDict=%s", respPaginatedTaskInfoDict)
</code>

某次的输出的效果是：

[2016-11-09 14:33:14,533 DEBUG User.py:541 get] type(taskPagination)=<class ‘flask_sqlalchemy.Pagination’>,taskPagination=<flask_sqlalchemy.Pagination object at 0x7f78b6847890>,has_next=False,has_prev=True,page=2,pages=2,per_page=10,total=14

[2016-11-09 14:33:14,533 DEBUG User.py:553 get] [0] eachTask.id=task-10b01105-ec53-41bb-810e-720ab468bdf7

[2016-11-09 14:33:14,560 DEBUG User.py:553 get] [1] eachTask.id=task-f3c0c660-e7f5-4583-bab2-23c7006dadc4

[2016-11-09 14:33:14,582 DEBUG User.py:553 get] [2] eachTask.id=task-f7a4d0df-3142-444b-a962-83660acd447f

[2016-11-09 14:33:14,599 DEBUG User.py:553 get] [3] eachTask.id=task-da013992-e7aa-4ae9-8b6f-bdf621b9fbaa

[2016-11-09 14:33:14,615 DEBUG User.py:566 get] respPaginatedTaskInfoDict={‘tasks’: {u’task-da013992-e7aa-4ae9-8b6f-bdf621b9fbaa’: OrderedDict([(‘hasEnded’, True), (‘itemType’, ‘Small’), (‘initiatorEndLocation’, OrderedDict([(‘fullStr’,。。。。。

。。。。

, (‘password’, None), (‘id’, None), (‘createdAt’, None), (‘errandorIsAuthenticated’, None)]))])}, ‘hasNext’: False, ‘totalPageNum’: 2, ‘hasPrev’: True, ‘numPerPage’: 10, ‘curPageNum’: 2, ‘totalNum’: 14L}

返回的json是：

{

“code”: 200,

“data”: {

“curPageNum”: 2,

“hasNext”: false,

“hasPrev”: true,

“numPerPage”: 10,

“tasks”: {

“task-10b01105-ec53-41bb-810e-720ab468bdf7”: {。。。},

“task-da013992-e7aa-4ae9-8b6f-bdf621b9fbaa”: {。。。},

“task-f3c0c660-e7f5-4583-bab2-23c7006dadc4”: {。。。},

“task-f7a4d0df-3142-444b-a962-83660acd447f”: {。。。}

“totalNum”: 14,

“totalPageNum”: 2

“message”: “get task/orders ok”

}

注：

此处的prev()有个bug，需要注意去规避：

【无需解决】Flask中SQLAlchemy中使用Pagination的prev出错：_mysql_exceptions ProgrammingError 1064 You have an error in your SQL syntax

对于上述的核心代码：

<code>taskPagination = Task.query.filter_by(errandorId=userId).paginate(
                page=curPageNum,
                per_page=numPerPage,
                error_out=False)
</code>

的具体解释：

1.query对象，可以去通过paginate得到一个Pagination的对象

比如：

<code>Task.query.filter_by(errandorId=userId)
</code>

得到的就是query对象

然后通过调用paginate，即可得到对应的Pagination对象

<code>type(taskPagination)=&lt;class 'flask_sqlalchemy.Pagination'&gt;,taskPagination=&lt;flask_sqlalchemy.Pagination object at 0x7f78b6847890&gt;
</code>

2.Pagination的对象中，最常用到的属性就是：

items：具体有多少个对象，是个列表

然后就可以通过items去获取每个对象的详细信息了。

其他还有一些常用属性：

page：当前的页数
pages：总的页数
per_page：每一页的个数
has_prev：是否有前一页
has_next：是否有后一页
total：（符合当前分页查询的）总（的项目的）个数

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