我无法弄清楚Snap 0.9中的路由奇怪(很可能还有其他版本)。我明白/是一种捕获所有模式的东西,除非我把ifTop函数放在处理程序中,对吗? 因此,使用(/,blah)路由,任何URL都应该由blah处理程序处理,是正确的吗?
使用由snap init,我不能得到快照来渲染除root.tpl之外的任何内容以获取根请求。
给定root(/,blah)和handler
blah :: Handler App App() blah = renderblah它会为任何网址提供blah模板,但会显示根网址! 所以/ anything呈现blah模板,但/呈现索引模板。
将blah处理程序更改为
blah = ifTop $ renderblah不会改变任何行为。 只有在这种情况下,我不能路由到/任何东西。路由到/仍呈现索引模板。 我错过了什么?如何获取/来呈现我选择的模板?
无论如何,它将用于呈现根页面。问题是 heistInit 函数: heistInit :: FilePath - ^模板路径 - > SnapletInit b(Heist b) heistInit templateDir = do makeSnapletheistNothing $ do hs < - heistInitWorker templateDir defaultHeistState addRoutes [(,heistServe) ] return hs您会发现它调用 addRoutes 。所以,如果你在添加你自己的路由之前调用 heistInit (默认模板确实如此),那么你的处理程序将不会有机会一个名字相同的模板(或者index.tpl的根目录)。
因此,只需将 addRoutes routes 放在 heistInit ( app 在默认模板中的Site.hs中)。
I can't figure out the routing strangeness in Snap 0.9 (and, most likely, other versions)
I understand "/" is a catch everything pattern unless I put ifTop function inside the handler, right? So, with ("/", blah) route, any URL should be handled by the blah handler, correct?
Playing with the default app generated by snap init, I can't get snap to render anything but index.tpl for the root request.
Given root ("/", blah) and handler
blah :: Handler App App () blah = render "blah"it renders blah template for any URL but the root URL! So "/anything" renders blah template but "/" renders index template.
Changing blah handler to
blah = ifTop $ render "blah"does not change the behavior whatsoever. Only in this case I cant route to "/anything". Routing to "/" still renders index template. What am I missing? How can I get "/" to render template of my choice?
解决方案If you have "index.tpl" template, then it will be used to render root page anyway. The issue is heistInit function:
heistInit :: FilePath -- ^ Path to templates -> SnapletInit b (Heist b) heistInit templateDir = do makeSnaplet "heist" "" Nothing $ do hs <- heistInitWorker templateDir defaultHeistState addRoutes [ ("", heistServe) ] return hsYou see that it calles addRoutes. So, if you call heistInit before adding your own routes (default template does that), then your handlers will not have even a chance if there is a template with the same name (or index.tpl for root).
So just place addRoutes routes above heistInit (app in Site.hs in default template).
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