[英]Running JS script from Java code in GraalVM native-image
I am experimenting with running JS scripts from Java code within a GraalVM native-image. 我正在尝试从GraalVM本机映像中的Java代码运行JS脚本。
The Java code looks like this: Java代码如下所示:
try (Context context = Context.create("js")) {
Value bindings = context.getBindings("js");
bindings.putMember("response", response);
bindings.putMember("UTF8", StandardCharsets.UTF_8);
context.eval("js", script);
} catch (PolyglotException e) {
error("Error: " + e, 10);
}
The JS code just tries to use the response
object by calling a method on it, for example: JS代码只是通过调用
response
对象来尝试使用response
对象,例如:
print("Status code: " + response.getStatusCode());
This works when running in GraalVM, but when creating a native-image, it fails with this error: 在GraalVM中运行时可以使用,但是在创建本机映像时会失败,并显示以下错误:
INVOKE on JavaObject[...] failed due to: Message not supported: INVOKE
If I just print the object as in print("Response: " + response);
如果我只是像
print("Response: " + response);
一样打印对象print("Response: " + response);
, it does not fail. ,它不会失败。 But if I attempt to call any method on
response
, I get this error (even toString()
or hashCode()
). 但是,如果尝试在
response
上调用任何方法,则会收到此错误(甚至是toString()
或hashCode()
)。
Is there something else I need to do or is this just a bug in SubstractVM native-image, currently? 目前,我还需要做其他事情吗?或者这仅仅是SubstractVM本机映像中的错误?
My GraalVM version: 我的GraalVM版本:
java version "1.8.0_172"
Java(TM) SE Runtime Environment (build 1.8.0_172-b11)
GraalVM 1.0.0-rc4 (build 25.71-b01-internal-jvmci-0.45, mixed mode)
native-image command I am using: 我正在使用的native-image命令:
native-image --language:js --report-unsupported-elements-at-runtime -jar my.jar
Update: as of RC 13 reflective access with native image is now supported. 更新:从RC 13开始,现在支持使用本机映像进行反射访问。 You need to provide a reflection config to native image.
您需要为本地映像提供一个反射配置。
Unfortunately GraalVM, as of RC5, doesn't yet support reflective access of Java objects when compiled using native-image. 不幸的是,从RC5开始,GraalVM在使用本机映像编译时还不支持Java对象的反射访问。 We plan to support this in one of the next release candidates.
我们计划在下一个发行候选版本中对此提供支持。
As a temporary workaround you may use the Proxy API like this: 作为临时的解决方法,您可以使用Proxy API,如下所示:
try (Context context = Context.create("js")) {
Map<String, Object> myObject = new HashMap<>();
myObject.put("foo", "bar");
context.getBindings("js").putMember("hostObject", ProxyObject.fromMap(myObject));
assert "bar".equals(context.eval("js", "hostObject.foo").asString());
myObject.put("foo", "baz");
assert "baz".equals(context.eval("js", "hostObject.foo").asString());
}
The Proxy API allows to mimic guest language values. 代理API允许模仿来宾语言值。
Here is another Proxy Example: http://www.graalvm.org/docs/graalvm-as-a-platform/embed/#computed-arrays-using-polyglot-proxies 这是另一个代理示例: http : //www.graalvm.org/docs/graalvm-as-a-platform/embed/#computed-arrays-using-polyglot-proxies
Proxy Javadoc: http://www.graalvm.org/sdk/javadoc/org/graalvm/polyglot/proxy/package-summary.html 代理Javadoc: http : //www.graalvm.org/sdk/javadoc/org/graalvm/polyglot/proxy/package-summary.html
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