rebol - 使用 READ/PART 或 READ/SEEK 从 url 部分读取

Question

通过 HTTP Range header 部分读取对我来说效果很好:

rebol []
client: open tcp://www.apache.org/

client/awake: func [event /local port] [
    port: event/port
    switch event/type [
        lookup [open port]
        connect [
            write port rejoin [
                {GET / HTTP/1.1} crlf
                {User-Agent: curl/7.26.0} crlf
                {Host: www.apache.org} crlf
                {Accept: */*} crlf
                {Range: bytes=0-9} crlf
                crlf
            ]
        ]
        wrote [read port]
        read [
            probe to-string port/data
            probe length? port/data
            clear port/data
        ]        
    ]
    false
]

wait [client 3]
close client
print "Done"

我想我可以使用 READ/PART 来做同样的事情:

length? read/part http://www.apache.org/ 10   ;40195
length? read http://www.apache.org/           ;40195

但它不起作用，仍然获取所有字节。与READ/SEEK相同。 为什么会这样？ (顺便说一下，它在 Rebol2 中有效。)

Answer 1

从源码中可以看到

https://github.com/rebol/rebol/blob/master/src/mezz/prot-http.r#L424

read actor 没有定义任何细化。这并不意味着它们不能被定义，但目前尚未决定是否应该通过使用细化或使用查询方言来完成。

通过设置trace/net on，您可以看到它在 Rebol2 中进行了伪造

>> trace/net on
>> read/part http://www.apache.org 10
URL Parse: none none www.apache.org none none none
Net-log: ["Opening" "tcp" "for" "HTTP"]
connecting to: www.apache.org
Net-log: {GET / HTTP/1.0
Accept: */*
Connection: close
User-Agent: REBOL View 2.7.8.3.1
Host: www.apache.org
}
Net-log: "HTTP/1.1 200 OK"
Net-log: ["low level read of " 2048 "bytes"]
Net-log: ["low level read of " 2048 "bytes"]
.. many lines removed
Net-log: ["low level read of " 2048 "bytes"]
Net-log: ["low level read of " 2048 "bytes"]
Net-log: ["low level read of " 2048 "bytes"]
== "<!DOCTYPE "