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8c741f6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 | /**
* @license
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import {
EnhancedGenerateContentResponse,
GenerateContentCandidate,
GenerateContentResponse,
GenerateContentStreamResult,
Part,
} from "../../types";
import { GoogleGenerativeAIError } from "../errors";
import { addHelpers } from "./response-helpers";
const responseLineRE = /^data\: (.*)(?:\n\n|\r\r|\r\n\r\n)/;
/**
* Process a response.body stream from the backend and return an
* iterator that provides one complete GenerateContentResponse at a time
* and a promise that resolves with a single aggregated
* GenerateContentResponse.
*
* @param response - Response from a fetch call
*/
export function processStream(response: Response): GenerateContentStreamResult {
const inputStream = response.body!.pipeThrough(
new TextDecoderStream("utf8", { fatal: true }),
);
const responseStream =
getResponseStream<GenerateContentResponse>(inputStream);
const [stream1, stream2] = responseStream.tee();
return {
stream: generateResponseSequence(stream1),
response: getResponsePromise(stream2),
};
}
async function getResponsePromise(
stream: ReadableStream<GenerateContentResponse>,
): Promise<EnhancedGenerateContentResponse> {
const allResponses: GenerateContentResponse[] = [];
const reader = stream.getReader();
while (true) {
const { done, value } = await reader.read();
if (done) {
return addHelpers(aggregateResponses(allResponses));
}
allResponses.push(value);
}
}
async function* generateResponseSequence(
stream: ReadableStream<GenerateContentResponse>,
): AsyncGenerator<EnhancedGenerateContentResponse> {
const reader = stream.getReader();
while (true) {
const { value, done } = await reader.read();
if (done) {
break;
}
yield addHelpers(value);
}
}
/**
* Reads a raw stream from the fetch response and join incomplete
* chunks, returning a new stream that provides a single complete
* GenerateContentResponse in each iteration.
*/
export function getResponseStream<T>(
inputStream: ReadableStream<string>,
): ReadableStream<T> {
const reader = inputStream.getReader();
const stream = new ReadableStream<T>({
start(controller) {
let currentText = "";
return pump();
function pump(): Promise<(() => Promise<void>) | undefined> {
return reader.read().then(({ value, done }) => {
if (done) {
if (currentText.trim()) {
controller.error(
new GoogleGenerativeAIError("Failed to parse stream"),
);
return;
}
controller.close();
return;
}
currentText += value;
let match = currentText.match(responseLineRE);
let parsedResponse: T;
while (match) {
try {
parsedResponse = JSON.parse(match[1]);
} catch (e) {
controller.error(
new GoogleGenerativeAIError(
`Error parsing JSON response: "${match[1]}"`,
),
);
return;
}
controller.enqueue(parsedResponse);
currentText = currentText.substring(match[0].length);
match = currentText.match(responseLineRE);
}
return pump();
});
}
},
});
return stream;
}
/**
* Aggregates an array of `GenerateContentResponse`s into a single
* GenerateContentResponse.
*/
export function aggregateResponses(
responses: GenerateContentResponse[],
): GenerateContentResponse {
const lastResponse = responses[responses.length - 1];
const aggregatedResponse: GenerateContentResponse = {
promptFeedback: lastResponse?.promptFeedback,
};
for (const response of responses) {
if (response.candidates) {
for (const candidate of response.candidates) {
const i = candidate.index;
if (!aggregatedResponse.candidates) {
aggregatedResponse.candidates = [];
}
if (!aggregatedResponse.candidates[i]) {
aggregatedResponse.candidates[i] = {
index: candidate.index,
} as GenerateContentCandidate;
}
// Keep overwriting, the last one will be final
aggregatedResponse.candidates[i].citationMetadata =
candidate.citationMetadata;
aggregatedResponse.candidates[i].finishReason = candidate.finishReason;
aggregatedResponse.candidates[i].finishMessage =
candidate.finishMessage;
aggregatedResponse.candidates[i].safetyRatings =
candidate.safetyRatings;
/**
* Candidates should always have content and parts, but this handles
* possible malformed responses.
*/
if (candidate.content && candidate.content.parts) {
if (!aggregatedResponse.candidates[i].content) {
aggregatedResponse.candidates[i].content = {
role: candidate.content.role || "user",
parts: [],
};
}
const newPart: Partial<Part> = {};
for (const part of candidate.content.parts) {
if (part.text) {
newPart.text = part.text;
}
if (part.functionCall) {
newPart.functionCall = part.functionCall;
}
if (part.executableCode) {
newPart.executableCode = part.executableCode;
}
if (part.codeExecutionResult) {
newPart.codeExecutionResult = part.codeExecutionResult;
}
if (Object.keys(newPart).length === 0) {
newPart.text = "";
}
aggregatedResponse.candidates[i].content.parts.push(
newPart as Part,
);
}
}
}
}
if (response.usageMetadata) {
aggregatedResponse.usageMetadata = response.usageMetadata;
}
}
return aggregatedResponse;
}
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