I was a little bored tonight and had a thought; “can I find a way to add a random Pokédex and it’s National Pokédex number as a header to requests on my website?”
The answer is - quite simply - “yes”.
Cloudflare Workers
This website runs on Cloudflare’s content delivery network and as such I have access to Cloudflare Workers, allowing me to run arbitrary code at the edge for incoming requests.
Setting up a worker that picks a random Pokemon and injects it as a header is very simple, add a worker, write the code and add some routing to it.
Try it yourself
curl -sI https://kura.gg/ | grep "x-pokemon" x-pokemon: Eevee (#133)
The code
let pokemon = [ "Bulbasaur (#1)", "Ivysaur (#2)", "Venusaur (#3)", "Charmander (#4)", "Charmeleon (#5)", "Charizard (#6)", "Squirtle (#7)", "Wartortle (#8)", "Blastoise (#9)", "Caterpie (#10)", "Metapod (#11)", "Butterfree (#12)", "Weedle (#13)", "Kakuna (#14)", "Beedrill (#15)", "Pidgey (#16)", "Pidgeotto (#17)", "Pidgeot (#18)", "Rattata (#19)", "Raticate (#20)", "Spearow (#21)", "Fearow (#22)", "Ekans (#23)", "Arbok (#24)", "Pikachu (#25)", "Raichu (#26)", "Sandshrew (#27)", "Sandslash (#28)", "Nidoran♀ (#29)", "Nidorina (#30)", "Nidoqueen (#31)", "Nidoran♂ (#32)", "Nidorino (#33)", "Nidoking (#34)", "Clefairy (#35)", "Clefable (#36)", "Vulpix (#37)", "Ninetales (#38)", "Jigglypuff (#39)", "Wigglytuff (#40)", "Zubat (#41)", "Golbat (#42)", "Oddish (#43)", "Gloom (#44)", "Vileplume (#45)", "Paras (#46)", "Parasect (#47)", "Venonat (#48)", "Venomoth (#49)", "Diglett (#50)", "Dugtrio (#51)", "Meowth (#52)", "Persian (#53)", "Psyduck (#54)", "Golduck (#55)", "Mankey (#56)", "Primeape (#57)", "Growlithe (#58)", "Arcanine (#59)", "Poliwag (#60)", "Poliwhirl (#61)", "Poliwrath (#62)", "Abra (#63)", "Kadabra (#64)", "Alakazam (#65)", "Machop (#66)", "Machoke (#67)", "Machamp (#68)", "Bellsprout (#69)", "Weepinbell (#70)", "Victreebel (#71)", "Tentacool (#72)", "Tentacruel (#73)", "Geodude (#74)", "Graveler (#75)", "Golem (#76)", "Ponyta (#77)", "Rapidash (#78)", "Slowpoke (#79)", "Slowbro (#80)", "Magnemite (#81)", "Magneton (#82)", "Farfetch'd (#83)", "Doduo (#84)", "Dodrio (#85)", "Seel (#86)", "Dewgong (#87)", "Grimer (#88)", "Muk (#89)", "Shellder (#90)", "Cloyster (#91)", "Gastly (#92)", "Haunter (#93)", "Gengar (#94)", "Onix (#95)", "Drowzee (#96)", "Hypno (#97)", "Krabby (#98)", "Kingler (#99)", "Voltorb (#100)", "Electrode (#101)", "Exeggcute (#102)", "Exeggutor (#103)", "Cubone (#104)", "Marowak (#105)", "Hitmonlee (#106)", "Hitmonchan (#107)", "Lickitung (#108)", "Koffing (#109)", "Weezing (#110)", "Rhyhorn (#111)", "Rhydon (#112)", "Chansey (#113)", "Tangela (#114)", "Kangaskhan (#115)", "Horsea (#116)", "Seadra (#117)", "Goldeen (#118)", "Seaking (#119)", "Staryu (#120)", "Starmie (#121)", "Mr. Mime (#122)", "Scyther (#123)", "Jynx (#124)", "Electabuzz (#125)", "Magmar (#126)", "Pinsir (#127)", "Tauros (#128)", "Magikarp (#129)", "Gyarados (#130)", "Lapras (#131)", "Ditto (#132)", "Eevee (#133)", "Vaporeon (#134)", "Jolteon (#135)", "Flareon (#136)", "Porygon (#137)", "Omanyte (#138)", "Omastar (#139)", "Kabuto (#140)", "Kabutops (#141)", "Aerodactyl (#142)", "Snorlax (#143)", "Articuno (#144)", "Zapdos (#145)", "Moltres (#146)", "Dratini (#147)", "Dragonair (#148)", "Dragonite (#149)", "Mewtwo (#150)", "Mew (#151)", "Chikorita (#152)", "Bayleef (#153)", "Meganium (#154)", "Cyndaquil (#155)", "Quilava (#156)", "Typhlosion (#157)", "Totodile (#158)", "Croconaw (#159)", "Feraligatr (#160)", "Sentret (#161)", "Furret (#162)", "Hoothoot (#163)", "Noctowl (#164)", "Ledyba (#165)", "Ledian (#166)", "Spinarak (#167)", "Ariados (#168)", "Crobat (#169)", "Chinchou (#170)", "Lanturn (#171)", "Pichu (#172)", "Cleffa (#173)", "Igglybuff (#174)", "Togepi (#175)", "Togetic (#176)", "Natu (#177)", "Xatu (#178)", "Mareep (#179)", "Flaaffy (#180)", "Ampharos (#181)", "Bellossom (#182)", "Marill (#183)", "Azumarill (#184)", "Sudowoodo (#185)", "Politoed (#186)", "Hoppip (#187)", "Skiploom (#188)", "Jumpluff (#189)", "Aipom (#190)", "Sunkern (#191)", "Sunflora (#192)", "Yanma (#193)", "Wooper (#194)", "Quagsire (#195)", "Espeon (#196)", "Umbreon (#197)", "Murkrow (#198)", "Slowking (#199)", "Misdreavus (#200)", "Unown (#201)", "Wobbuffet (#202)", "Girafarig (#203)", "Pineco (#204)", "Forretress (#205)", "Dunsparce (#206)", "Gligar (#207)", "Steelix (#208)", "Snubbull (#209)", "Granbull (#210)", "Qwilfish (#211)", "Scizor (#212)", "Shuckle (#213)", "Heracross (#214)", "Sneasel (#215)", "Teddiursa (#216)", "Ursaring (#217)", "Slugma (#218)", "Magcargo (#219)", "Swinub (#220)", "Piloswine (#221)", "Corsola (#222)", "Remoraid (#223)", "Octillery (#224)", "Delibird (#225)", "Mantine (#226)", "Skarmory (#227)", "Houndour (#228)", "Houndoom (#229)", "Kingdra (#230)", "Phanpy (#231)", "Donphan (#232)", "Porygon2 (#233)", "Stantler (#234)", "Smeargle (#235)", "Tyrogue (#236)", "Hitmontop (#237)", "Smoochum (#238)", "Elekid (#239)", "Magby (#240)", "Miltank (#241)", "Blissey (#242)", "Raikou (#243)", "Entei (#244)", "Suicune (#245)", "Larvitar (#246)", "Pupitar (#247)", "Tyranitar (#248)", "Lugia (#249)", "Ho-Oh (#250)", "Celebi (#251)", "Treecko (#252)", "Grovyle (#253)", "Sceptile (#254)", "Torchic (#255)", "Combusken (#256)", "Blaziken (#257)", "Mudkip (#258)", "Marshtomp (#259)", "Swampert (#260)", "Poochyena (#261)", "Mightyena (#262)", "Zigzagoon (#263)", "Linoone (#264)", "Wurmple (#265)", "Silcoon (#266)", "Beautifly (#267)", "Cascoon (#268)", "Dustox (#269)", "Lotad (#270)", "Lombre (#271)", "Ludicolo (#272)", "Seedot (#273)", "Nuzleaf (#274)", "Shiftry (#275)", "Taillow (#276)", "Swellow (#277)", "Wingull (#278)", "Pelipper (#279)", "Ralts (#280)", "Kirlia (#281)", "Gardevoir (#282)", "Surskit (#283)", "Masquerain (#284)", "Shroomish (#285)", "Breloom (#286)", "Slakoth (#287)", "Vigoroth (#288)", "Slaking (#289)", "Nincada (#290)", "Ninjask (#291)", "Shedinja (#292)", "Whismur (#293)", "Loudred (#294)", "Exploud (#295)", "Makuhita (#296)", "Hariyama (#297)", "Azurill (#298)", "Nosepass (#299)", "Skitty (#300)", "Delcatty (#301)", "Sableye (#302)", "Mawile (#303)", "Aron (#304)", "Lairon (#305)", "Aggron (#306)", "Meditite (#307)", "Medicham (#308)", "Electrike (#309)", "Manectric (#310)", "Plusle (#311)", "Minun (#312)", "Volbeat (#313)", "Illumise (#314)", "Roselia (#315)", "Gulpin (#316)", "Swalot (#317)", "Carvanha (#318)", "Sharpedo (#319)", "Wailmer (#320)", "Wailord (#321)", "Numel (#322)", "Camerupt (#323)", "Torkoal (#324)", "Spoink (#325)", "Grumpig (#326)", "Spinda (#327)", "Trapinch (#328)", "Vibrava (#329)", "Flygon (#330)", "Cacnea (#331)", "Cacturne (#332)", "Swablu (#333)", "Altaria (#334)", "Zangoose (#335)", "Seviper (#336)", "Lunatone (#337)", "Solrock (#338)", "Barboach (#339)", "Whiscash (#340)", "Corphish (#341)", "Crawdaunt (#342)", "Baltoy (#343)", "Claydol (#344)", "Lileep (#345)", "Cradily (#346)", "Anorith (#347)", "Armaldo (#348)", "Feebas (#349)", "Milotic (#350)", "Castform (#351)", "Kecleon (#352)", "Shuppet (#353)", "Banette (#354)", "Duskull (#355)", "Dusclops (#356)", "Tropius (#357)", "Chimecho (#358)", "Absol (#359)", "Wynaut (#360)", "Snorunt (#361)", "Glalie (#362)", "Spheal (#363)", "Sealeo (#364)", "Walrein (#365)", "Clamperl (#366)", "Huntail (#367)", "Gorebyss (#368)", "Relicanth (#369)", "Luvdisc (#370)", "Bagon (#371)", "Shelgon (#372)", "Salamence (#373)", "Beldum (#374)", "Metang (#375)", "Metagross (#376)", "Regirock (#377)", "Regice (#378)", "Registeel (#379)", "Latias (#380)", "Latios (#381)", "Kyogre (#382)", "Groudon (#383)", "Rayquaza (#384)", "Jirachi (#385)", "Deoxys (#386)", "Turtwig (#387)", "Grotle (#388)", "Torterra (#389)", "Chimchar (#390)", "Monferno (#391)", "Infernape (#392)", "Piplup (#393)", "Prinplup (#394)", "Empoleon (#395)", "Starly (#396)", "Staravia (#397)", "Staraptor (#398)", "Bidoof (#399)", "Bibarel (#400)", "Kricketot (#401)", "Kricketune (#402)", "Shinx (#403)", "Luxio (#404)", "Luxray (#405)", "Budew (#406)", "Roserade (#407)", "Cranidos (#408)", "Rampardos (#409)", "Shieldon (#410)", "Bastiodon (#411)", "Burmy (#412)", "Wormadam (#413)", "Mothim (#414)", "Combee (#415)", "Vespiquen (#416)", "Pachirisu (#417)", "Buizel (#418)", "Floatzel (#419)", "Cherubi (#420)", "Cherrim (#421)", "Shellos (#422)", "Gastrodon (#423)", "Ambipom (#424)", "Drifloon (#425)", "Drifblim (#426)", "Buneary (#427)", "Lopunny (#428)", "Mismagius (#429)", "Honchkrow (#430)", "Glameow (#431)", "Purugly (#432)", "Chingling (#433)", "Stunky (#434)", "Skuntank (#435)", "Bronzor (#436)", "Bronzong (#437)", "Bonsly (#438)", "Mime Jr. (#439)", "Happiny (#440)", "Chatot (#441)", "Spiritomb (#442)", "Gible (#443)", "Gabite (#444)", "Garchomp (#445)", "Munchlax (#446)", "Riolu (#447)", "Lucario (#448)", "Hippopotas (#449)", "Hippowdon (#450)", "Skorupi (#451)", "Drapion (#452)", "Croagunk (#453)", "Toxicroak (#454)", "Carnivine (#455)", "Finneon (#456)", "Lumineon (#457)", "Mantyke (#458)", "Snover (#459)", "Abomasnow (#460)", "Weavile (#461)", "Magnezone (#462)", "Lickilicky (#463)", "Rhyperior (#464)", "Tangrowth (#465)", "Electivire (#466)", "Magmortar (#467)", "Togekiss (#468)", "Yanmega (#469)", "Leafeon (#470)", "Glaceon (#471)", "Gliscor (#472)", "Mamoswine (#473)", "Porygon-Z (#474)", "Gallade (#475)", "Probopass (#476)", "Dusknoir (#477)", "Froslass (#478)", "Rotom (#479)", "Uxie (#480)", "Mesprit (#481)", "Azelf (#482)", "Dialga (#483)", "Palkia (#484)", "Heatran (#485)", "Regigigas (#486)", "Giratina (#487)", "Cresselia (#488)", "Phione (#489)", "Manaphy (#490)", "Darkrai (#491)", "Shaymin (#492)", "Arceus (#493)", "Victini (#494)", "Snivy (#495)", "Servine (#496)", "Serperior (#497)", "Tepig (#498)", "Pignite (#499)", "Emboar (#500)", "Oshawott (#501)", "Dewott (#502)", "Samurott (#503)", "Patrat (#504)", "Watchog (#505)", "Lillipup (#506)", "Herdier (#507)", "Stoutland (#508)", "Purrloin (#509)", "Liepard (#510)", "Pansage (#511)", "Simisage (#512)", "Pansear (#513)", "Simisear (#514)", "Panpour (#515)", "Simipour (#516)", "Munna (#517)", "Musharna (#518)", "Pidove (#519)", "Tranquill (#520)", "Unfezant (#521)", "Blitzle (#522)", "Zebstrika (#523)", "Roggenrola (#524)", "Boldore (#525)", "Gigalith (#526)", "Woobat (#527)", "Swoobat (#528)", "Drilbur (#529)", "Excadrill (#530)", "Audino (#531)", "Timburr (#532)", "Gurdurr (#533)", "Conkeldurr (#534)", "Tympole (#535)", "Palpitoad (#536)", "Seismitoad (#537)", "Throh (#538)", "Sawk (#539)", "Sewaddle (#540)", "Swadloon (#541)", "Leavanny (#542)", "Venipede (#543)", "Whirlipede (#544)", "Scolipede (#545)", "Cottonee (#546)", "Whimsicott (#547)", "Petilil (#548)", "Lilligant (#549)", "Basculin (#550)", "Sandile (#551)", "Krokorok (#552)", "Krookodile (#553)", "Darumaka (#554)", "Darmanitan (#555)", "Maractus (#556)", "Dwebble (#557)", "Crustle (#558)", "Scraggy (#559)", "Scrafty (#560)", "Sigilyph (#561)", "Yamask (#562)", "Cofagrigus (#563)", "Tirtouga (#564)", "Carracosta (#565)", "Archen (#566)", "Archeops (#567)", "Trubbish (#568)", "Garbodor (#569)", "Zorua (#570)", "Zoroark (#571)", "Minccino (#572)", "Cinccino (#573)", "Gothita (#574)", "Gothorita (#575)", "Gothitelle (#576)", "Solosis (#577)", "Duosion (#578)", "Reuniclus (#579)", "Ducklett (#580)", "Swanna (#581)", "Vanillite (#582)", "Vanillish (#583)", "Vanilluxe (#584)", "Deerling (#585)", "Sawsbuck (#586)", "Emolga (#587)", "Karrablast (#588)", "Escavalier (#589)", "Foongus (#590)", "Amoonguss (#591)", "Frillish (#592)", "Jellicent (#593)", "Alomomola (#594)", "Joltik (#595)", "Galvantula (#596)", "Ferroseed (#597)", "Ferrothorn (#598)", "Klink (#599)", "Klang (#600)", "Klinklang (#601)", "Tynamo (#602)", "Eelektrik (#603)", "Eelektross (#604)", "Elgyem (#605)", "Beheeyem (#606)", "Litwick (#607)", "Lampent (#608)", "Chandelure (#609)", "Axew (#610)", "Fraxure (#611)", "Haxorus (#612)", "Cubchoo (#613)", "Beartic (#614)", "Cryogonal (#615)", "Shelmet (#616)", "Accelgor (#617)", "Stunfisk (#618)", "Mienfoo (#619)", "Mienshao (#620)", "Druddigon (#621)", "Golett (#622)", "Golurk (#623)", "Pawniard (#624)", "Bisharp (#625)", "Bouffalant (#626)", "Rufflet (#627)", "Braviary (#628)", "Vullaby (#629)", "Mandibuzz (#630)", "Heatmor (#631)", "Durant (#632)", "Deino (#633)", "Zweilous (#634)", "Hydreigon (#635)", "Larvesta (#636)", "Volcarona (#637)", "Cobalion (#638)", "Terrakion (#639)", "Virizion (#640)", "Tornadus (#641)", "Thundurus (#642)", "Reshiram (#643)", "Zekrom (#644)", "Landorus (#645)", "Kyurem (#646)", "Keldeo (#647)", "Meloetta (#648)", "Genesect (#649)", "Chespin (#650)", "Quilladin (#651)", "Chesnaught (#652)", "Fennekin (#653)", "Braixen (#654)", "Delphox (#655)", "Froakie (#656)", "Frogadier (#657)", "Greninja (#658)", "Bunnelby (#659)", "Diggersby (#660)", "Fletchling (#661)", "Fletchinder (#662)", "Talonflame (#663)", "Scatterbug (#664)", "Spewpa (#665)", "Vivillon (#666)", "Litleo (#667)", "Pyroar (#668)", "Flabebe (#669)", "Floette (#670)", "Florges (#671)", "Skiddo (#672)", "Gogoat (#673)", "Pancham (#674)", "Pangoro (#675)", "Furfrou (#676)", "Espurr (#677)", "Meowstic (#678)", "Honedge (#679)", "Doublade (#680)", "Aegislash (#681)", "Spritzee (#682)", "Aromatisse (#683)", "Swirlix (#684)", "Slurpuff (#685)", "Inkay (#686)", "Malamar (#687)", "Binacle (#688)", "Barbaracle (#689)", "Skrelp (#690)", "Dragalge (#691)", "Helioptile (#694)", "Heliolisk (#695)", "Tyrunt (#696)", "Tyrantrum (#697)", "Amaura (#698)", "Aurorus (#699)", "Sylveon (#700)", "Hawlucha (#701)", "Dedenne (#702)", "Carbink (#703)", "Goomy (#704)", "Sliggoo (#705)", "Goodra (#706)", "Klefki (#707)", "Phantump (#708)", "Trevenant (#709)", "Pumpkaboo (#710)", "Gourgeist (#711)", "Bergmite (#712)", "Avalugg (#713)", "Noibat (#714)", "Noivern (#715)", "Xerneas (#716)", "Yveltal (#717)", "Zygarde (#718)", "Diancie (#719)", "Hoopa (#720)", "Volcanion (#721)", "Rowlet (#722)", "Dartrix (#723)", "Decidueye (#724)", "Litten (#725)", "Torracat (#726)", "Incineroar (#727)", "Popplio (#728)", "Brionne (#729)", "Primarina (#730)", "Pikipek (#731)", "Trumbeak (#732)", "Toucannon (#733)", "Yungoos (#734)", "Gumshoos (#735)", "Grubbin (#736)", "Charjabug (#737)", "Vikavolt (#738)", "Crabrawler (#739)", "Crabominable (#740)", "Oricorio (#741)", "Cutiefly (#742)", "Ribombee (#743)", "Rockruff (#744)", "Lycanroc (#745)", "Wishiwashi (#746)", "Mareanie (#747)", "Toxapex (#748)", "Mudbray (#749)", "Mudsdale (#750)", "Dewpider (#751)", "Araquanid (#752)", "Fomantis (#753)", "Lurantis (#754)", "Morelull (#755)", "Shiinotic (#756)", "Salandit (#757)", "Salazzle (#758)", "Stufful (#759)", "Bewear (#760)", "Bounsweet (#761)", "Steenee (#762)", "Tsareena (#763)", "Comfey (#764)", "Oranguru (#765)", "Passimian (#766)", "Wimpod (#767)", "Golisopod (#768)", "Sandygast (#769)", "Palossand (#770)", "Pyukumuku (#771)", "Type: Null (#772)", "Silvally (#773)", "Minior (#774)", "Komala (#775)", "Turtonator (#776)", "Togedemaru (#777)", "Mimikyu (#778)", "Bruxish (#779)", "Drampa (#780)", "Dhelmise (#781)", "Jangmo-o (#782)", "Hakamo-o (#783)", "Kommo-o (#784)", "Tapu Koko (#785)", "Tapu Lele (#786)", "Tapu Bulu (#787)", "Tapu Fini (#788)", "Cosmog (#789)", "Cosmoem (#790)", "Solgaleo (#791)", "Lunala (#792)", "Nihilego (#793)", "Buzzwole (#794)", "Pheromosa (#795)", "Xurkitree (#796)", "Celesteela (#797)", "Kartana (#798)", "Guzzlord (#799)", "Necrozma (#800)", "Magearna (#801)", "Marshadow (#802)", "Poipole (#803)", "Naganadel (#804)", "Stakataka (#805)", "Blacephalon (#806)", "Zeraora (#807)", "Meltan (#808)", "Melmetal (#809)", "Grookey (#810)", "Thwackey (#811)", "Rillaboom (#812)", "Scorbunny (#813)", "Raboot (#814)", "Cinderace (#815)", "Sobble (#816)", "Drizzile (#817)", "Inteleon (#818)", "Skwovet (#819)", "Greedent (#820)", "Rookidee (#821)", "Convisquire (#822)", "Conviknight (#823)", "Blipbug (#824)", "Dottler (#825)", "Orbeetle (#826)", "Nickit (#827)", "Thievul (#828)", "Gossifleur (#829)", "Eldegoss (#830)", "Wooloo (#831)", "Dubwool (#832)", "Chewtle (#833)", "Drednaw (#834)", "Yamper (#835)", "Boltund (#836)", "Rolycoly (#837)", "Carkol (#838)", "Coalossal (#839)", "Applin (#840)", "Flapple (#841)", "Appletun (#842)", "Silicobra (#843)", "Sandaconda (#844)", "Cramorant (#845)", "Arrokuda (#846)", "Barraskewda (#847)", "Toxel (#848)", "Toxtricity (#849)", "Sizzlipede (#850)", "Centiskorch (#851)", "Clobbopus (#852)", "Grapploct (#853)", "Sinistea (#854)", "Polteageist (#855)", "Hatenna (#856)", "Hattrem (#857)", "Hatterene (#858)", "Impidimp (#859)", "Morgrem (#860)", "Grimmsnarl (#861)", "Obstagoon (#862)", "Perrserker (#863)", "Cursola (#864)", "Sirfetch'd (#865)", "Mr. Rime (#866)", "Runerigus (#867)", "Milcery (#868)", "Alcremie (#869)", "Falinks (#870)", "Pincurchin (#871)", "Snom (#872)", "Frosmoth (#873)", "Stonjourner (#874)", "Eiscue (#875)", "Indeedee (#876)", "Morpeko (#877)", "Cufant (#878)", "Copperajah (#879)", "Dracozolt (#880)", "Arctozolt (#881)", "Dracovish (#882)", "Arctovish (#883)", "Duraludon (#884)", "Dreepy (#885)", "Drakloak (#886)", "Dragapult (#887)", "Zacian (#888)", "Zamazanta (#889)", "Eternatus (#890)", "Kubfu (#891)", "Urshifu (#892)", "Zarude (#893)", "Regieleki (#894)", "Regidrago (#895)", "Glastrier (#896)", "Spectrier (#897)", "Calyrex (#898)" ] async function handle_request(request) { let response = await fetch(request) let new_headers = new Headers(response.headers) new_headers.set("X-Pokemon", pokemon[(Math.random() * pokemon.length | 0)]) return new Response(response.body, { status: response.status, statusText: response.statusText, headers: new_headers }) } addEventListener('fetch', event => { event.respondWith(handle_request(event.request)) })
