ngx.var vs ngx.ctx

[ktalebian]

What is the different between ngx.var and ngx.ctx? I know var can only hold string values, while ctx can hold any variable, so it seems like it's easier to use ngx.ctx all the time.

Does the ctx persist through internal proxies? Does it have any performance issues? When should one use var or ctx?

[agentzh]

@ktalebian Use ngx.ctx wherever you can. ngx.var is much more expensive and is also limited to string values. The latter should only be used to exchange data with other nginx C modules.

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