Queue versioning

A method to be performed by a playback device, the method comprising:

• initiating playback of a queue including one or more first audio streams, wherein a queue identification token stored in data storage of the playback device represents a current version of the queue;
• after initiating the playback, receiving, via a network interface of the playback device from a computing system, data representing instructions to add one or more second audio streams to the queue, the instructions comprising:
• (i) an indication of the one or more second audio streams, the one or more second audio streams including a particular audio stream;
• (ii) a universal resource identifier (URI) representing a location of the particular audio stream at one or more servers of a streaming audio service;
• and (iii) a first token representing an expected queue version;
• determining whether the expected queue version represented by the first token matches the current version of the queue represented by the queue identification token;
• if the expected queue version represented by the first token matches the current version of the queue represented by the queue identification token, adding the one or more second audio streams to the queue according to the received instructions to add one or more second audio streams to the queue;
• and
• if the expected queue version represented by the first token differs from the current version of the queue represented by the queue identification token, foregoing adding the one or more second audio streams to the queue according to the received instructions to add one or more second audio streams to the queue.

A non-transitory computer-readable medium having stored therein instructions executable by one or more processors to cause a playback device to perform functions comprising:

• initiating playback of a queue including one or more first audio streams, wherein a queue identification token stored in data storage of the playback device represents a current version of the queue;
• after initiating the playback, receiving, via a network interface of the playback device from a computing system, data representing instructions to add one or more second audio streams to the queue, the instructions comprising:
• (i) an indication of the one or more second audio streams, the one or more second audio streams including a particular audio stream;
• (ii) a universal resource identifier (URI) representing a location of the particular audio stream at one or more servers of a streaming audio service;
• and (iii) a first token representing an expected queue version;
• determining whether the expected queue version represented by the first token matches the current version of the queue represented by the queue identification token;
• if the expected queue version represented by the first token matches the current version of the queue represented by the queue identification token, adding the one or more second audio streams to the queue according to the received instructions to add one or more second audio streams to the queue;
• and
• if the expected queue version represented by the first token differs from the current version of the queue represented by the queue identification token, foregoing adding the one or more second audio streams to the queue according to the received instructions to add one or more second audio streams to the queue.