Web2py SQLFORM 更新或插入取决于在回调中检查的记录存在

Question

我遇到了以下挑战。

我可以使用回调函数来决定是更新记录还是在 form.process() 调用中插入新记录？

简单地说，我需要一个 SQLFORM，用户将使用文本引用标识符和可选的要上传的文件来填充它。也就是说，他们应该能够上传带有引用的文件，或者只是插入一个新引用并稍后添加其文件但通过相同的 SQLFORM。

型号：

db.define_table('t_object_occurence',
    Field('f_refid', type='string', label=T('Reference')),
    Field('f_object_id', db.t_object, label=T('Object')),
    Field('f_temp_file', type='upload', label=T('File'), autodelete=True)
    #more fileds
)

每当用户选择一个文件时，一些 jQuery 会根据文件名（正式定义）更新 ref id 字段。

查看：

{{if auth.has_permission('Object_occurence_UL'):}}
<h2>Add a new occurence</h2>
    {{=upload_form}}
{{pass}}
<h2>Latest occurences</h2>
{{=grid}}
<!-- some jQuery -->

然后，通过 form.process() 调用的回调函数执行以下检查（以及其他检查范围之外的检查）：

1. 如果不存在具有相同 ref id 的记录，则此表单必须生成 db insert。有或没有上传的文件。
2. 如果是这样，主要有两种情况：
   1. 现有记录已经上传文件，然后应该引发表单错误 => 完成
   2. 或者，如果此记录没有其文件，那么我希望它通过上传归档的文件进行更新。

控制器：

def object_browse():
    obj = db.t_object(request.args[0])
    upload_form = SQLFORM(db.t_object_occurence, fields=['f_refid', 'f_temp_file'])
    # recall object ID in form parameters
    upload_form.vars.f_object_id = long(request.args[0])
    # perform field values checks with specific function analyse_occurence_data()
    if upload_form.process(onvalidation=analyse_occurence_data).accepted:
        if upload_form.vars.f_temp_file != '':
            response.flash = "File upload OK, occurence " + str(upload_form.vars.f_refid) + " added to repository"
        else:
            response.flash = "New forcasted occurence added " + str(upload_form.vars.f_refid)
        redirect(URL('object_browse', args=[str(obj.id)], user_signature=True))
    # display occurence list
    query = (db.t_object_occurence.f_object_id==long(request.args[0]))
    grid = SQLFORM.grid(...)
    return dict(upload_form=upload_form, grid=grid)

检查回调函数：

def analyse_occurence_data(form):
    import types
    if isinstance(form.vars.f_temp_file, types.StringType):
        filename = None
    else:
        filename = form.vars.f_temp_file.filename
    occurence = form.vars.f_refid
    object_id = form.vars.f_object_id
    obj = db.t_object(object_id)
    # several checks and complementary form.vars.field = value
    potential_entry = db((db.t_object_occurence.f_refid==occurence)&(db.t_object_occurence.f_object_id==object_id)).select().first()
    if potential_entry is None:
        # let's insert a new record!
        return
    elif (filename is None) or (potential_entry.f_temp_file is not None):
        form.errors.f_temp_file = "The occurence "+occurence+" of "+obj.f_refid+" already exists in repository."
    elif potential_entry is not None:
            # THIS IS WHERE I'd like to decide to update instead of insert!

由于我的应用程序在调用其回调之前无法知道它是否必须插入或更新记录，因此我正在寻找正确的指令，以便我的 SQLFORM 能够做正确的事情。

非常感谢。

Answer 1

这是一个可以帮助您调整上述代码的工作示例：

def onvalidation_insert_or_update(form):
    row = db(db.mytable.f1 == form.vars.f1).select(db.mytable.ALL).first()
    if row is not None:
        id = row.id
        db(db.mytable.id == id).update(f2=form.vars.f2)
        session.flash = 'Record updated'
    else:
        id = db.mytable.insert(**form.vars)
        session.flash = 'Record inserted'
    db.commit()
    session.flash = 'Record inserted'
    redirect(URL(c='default', f='read_form', args=id))
    return


def basic_controller():
    form = SQLFORM(db.mytable)
    if form.process(dbio=False, onvalidation=onvalidation_insert_or_update).accepted:
        pass
    elif form.errors:
        response.flash = 'form has errors'
    else:
        response.flash = 'please fill the form'
    grid = SQLFORM.grid(db.mytable)
    return dict(form=form, grid=grid)

def read_form():
    form = SQLFORM(db.mytable, record=request.args(0), readonly=True)  # readonly=True make form not modifiable
    return dict(form=form)

我无法附加工作应用程序...但也许，如果您向 web2py 用户 google 组提出您的问题，我可以将其与电子邮件一起附加，这对于此类问题来说更方便。