将 drakma http-request 数组写入文件
我想做的： 获取 (drakma:http-request "someURL.jpg") 的输出并将其写入文件。输出由字节数组组成。
我想到了什么：
(with-open-file (my-stream "thing.jpg"
:direction :output
:element-type 'binary
:if-does-not-exist :create
:if-exists :supersede)
(let ((content (drakma:http-request "someURL.jpg")))
(loop for i across content do
(write-byte i my-stream))))
我得到的错误：
debugger invoked on a SIMPLE-ERROR in thread #<THREAD "initial thread" RUNNING
{1002978FB1}>:
could not find any output routine for :FULL buffered BINARY
我使用 SBCL 1.0.49。 如果您想要任何其他信息或发现我的问题不清楚，请询问:)。
编辑： 问题是：元素类型，它应该是“无符号字节”。 您可以在 Common Lisp Hyper Spec 的
附言。我无法回复作为答案，因为我的声誉太低。
What I want to do:
take the output of (drakma:http-request "someURL.jpg") and write it to a file. The output consists of a byte array.
What I came up with:
(with-open-file (my-stream "thing.jpg"
:direction :output
:element-type 'binary
:if-does-not-exist :create
:if-exists :supersede)
(let ((content (drakma:http-request "someURL.jpg")))
(loop for i across content do
(write-byte i my-stream))))
The error I get:
debugger invoked on a SIMPLE-ERROR in thread #<THREAD "initial thread" RUNNING
{1002978FB1}>:
could not find any output routine for :FULL buffered BINARY
I use SBCL 1.0.49.
If you want any other info or find my question unclear then please, ask away :).
EDIT:
The problem is the :element-type, it's supposed to be 'unsigned-byte.
You can find information on the different possibilities of :element-type over at the Common Lisp Hyper Spec under open . Other than that everything is correct.
PS. I couldn't respond as an answer because my reputation is too low.
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评论（1）
正如 Xach 所说，你最好使用
'(unsigned-byte 8)（或进行类型定义，例如(deftype binary () '(unsigned-byte 8))< /代码>）。此外，您可以通过调用 write-sequence 来替换数组上的循环并逐字节写入
As Xach said, you're better off using
'(unsigned-byte 8)(or make a type-definition , e.g.(deftype binary () '(unsigned-byte 8))).In addition, you can probably replace your loop over the array and writing byte by byte with a call to
write-sequence