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https://issues.apache.org/jira/browse/THRIFT-1976?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14216975#comment-14216975
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Randy Abernethy commented on THRIFT-1976:
-----------------------------------------
This is not a nice problem and it is not unique to JavaScript. Python has
similar constraints for example. I think we need to decide if we want to
document the fact that many scripting languages do not support complex keys or
if we want to make scripting language maps a lot less easy to code in scripting
languages (which would be fairly contra to the main reason for using them). Not
sure what other think.
> Javascript client unable to serialize/deserialize maps with struct keys
> -----------------------------------------------------------------------
>
> Key: THRIFT-1976
> URL: https://issues.apache.org/jira/browse/THRIFT-1976
> Project: Thrift
> Issue Type: Bug
> Components: JavaScript - Compiler, JavaScript - Library
> Affects Versions: 0.9
> Environment: All
> Reporter: Andrew Stanton
>
> The Javascript compiler is unable to serialize maps where a struct is a key
> due to particularities with how Javascript treats {} objects.
> Using the following thrift definition:
> struct Foo {
> 1: required string name;
> }
> struct Bar {
> 1: required string description;
> }
> struct Mapper {
> 1: required map<Foo,Bar> fooToBar;
> }
> /* End */
> It produces the following javascript code:
> /* Start -Snipped */
> Mapper.prototype.write = function(output) {
> output.writeStructBegin('Mapper');
> if (this.fooToBar !== null && this.fooToBar !== undefined) {
> output.writeFieldBegin('fooToBar', Thrift.Type.MAP, 1);
> output.writeMapBegin(Thrift.Type.STRUCT, Thrift.Type.STRUCT,
> Thrift.objectLength(this.fooToBar));
> // XXX
> // This will always fail as kiter8 will always be a String
> // XXX
> for (var kiter8 in this.fooToBar)
> {
> if (this.fooToBar.hasOwnProperty(kiter8))
> {
> var viter9 = this.fooToBar[kiter8];
> // kiter8 is a string, not an object.
> kiter8.write(output);
> viter9.write(output);
> }
> }
> output.writeMapEnd();
> output.writeFieldEnd();
> }
> output.writeFieldStop();
> output.writeStructEnd();
> return;
> };
> /* END */
> This code always fails since enumeration of an object's keys will always
> yield String values. I've annotated the relevant parts in the above code.
> There isn't really a simple fix for this either: Using for-in, there is no
> way to get a reference to the original key object. Practically, a Map type
> would have to be added to the thrift library with basic put()/get()/delete()
> operations to allow for struct maps.
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