1. A computer-implemented method for repairing URL (Uniform Resource Locator) request messages from user computing devices, the method comprising: receiving a URL request from a user computing device, the URL request specifying a URL that includes a name of a domain followed by a character string, the character string including a first product identifier; determining that the URL is invalid; at least partly in response to receiving the invalid URL, processing the invalid URL into a repaired URL using one or more computing devices, the repaired URL being different from the invalid URL, the processing comprising: identifying a non-URL escape sequence in the character string through a comparison with known escape sequences, the escape sequence corresponding to a special character; replacing the non-URL escape sequence in the character string with the corresponding special character; and decoding the URL a second time by replacing a URL escape sequence in the character string with a corresponding special character, wherein the URL was previously decoded a first time; and in response to determining whether the repaired URL resolves to valid content, (1) providing the valid content associated with the repaired URL to the user computing device when the repaired URL is valid or (2) identifying, using the first product identifier extracted from the invalid URL, a substitute URL and providing content associated with the substitute URL when the repaired URL is invalid.
1. A computer-implemented method for repairing URL (Uniform Resource Locator) request messages from user computing devices, the method comprising: receiving a URL request from a user computing device, the URL request specifying a URL that includes a name of a domain followed by a character string, the character string including a first product identifier; determining that the URL is invalid; at least partly in response to receiving the invalid URL, processing the invalid URL into a repaired URL using one or more computing devices, the repaired URL being different from the invalid URL, the processing comprising: identifying a non-URL escape sequence in the character string through a comparison with known escape sequences, the escape sequence corresponding to a special character; replacing the non-URL escape sequence in the character string with the corresponding special character; and decoding the URL a second time by replacing a URL escape sequence in the character string with a corresponding special character, wherein the URL was previously decoded a first time; and in response to determining whether the repaired URL resolves to valid content, (1) providing the valid content associated with the repaired URL to the user computing device when the repaired URL is valid or (2) identifying, using the first product identifier extracted from the invalid URL, a substitute URL and providing content associated with the substitute URL when the repaired URL is invalid. 6. The method of claim 1 , wherein the processing further comprises decoding the URL at least two times.